Agreed. Get a friend or someone you really trust to take a look for you. I usually assemble and diagnose faults myself, using the Internet for researching guidelines.
Most "repair" shops here in Singapore are of the very shady sort. Most of them are run by people who have no certifications, and their shops don't win any credibility. I've also had horror stories from friends who were charged exorbitant rates by the shops, yet the guesstimated cost of the parts weren't even 50% of what they were charged.
Bottom line is: fix it yourself or just get a new one.

Getting a computer repaired is always cause for concern. There's only one computer store in my town that is trustworthy--I worked there once and I have seen first-hand that they know what they are doing. They have high prices, but at least they do what they promise and don't try to fix a faulty RAM module by reinstalling Windows. The rest are totally dodgy. Having faded copies of the likes of Diablo and Homeworld sitting in their shop window for longer than I'd like to contemplate doesn't help appearances, and when it comes to servicing their mistakes range from somewhat minor things like automatically disabling the "useless" UAC without asking the customer (which makes the configuration files and save data of any legacy software the user has no longer accessible--oops!) right up to doing half a job and charging the whole price for it.
On one occasion I was contacted about computer problems remaining after a technician had taken a system away to "service" it. I don't remember what it was he was supposedly fixing (nor whether he actually fixed it), but unlike the store I worked for his off-site servicing routine apparently didn't include running a defrag, updating Windows Update and AVG (perhaps he charges more for those extra clicks?). To top it all off, when he returned the computer he plugged the speakers into the wrong sound jack. To be fair their sound card had two green sound jacks side by side (for some reason) so it wasn't as stupid as plugging it into the headphone jack, but he clearly hadn't paid any attention, and the end result was that he had fixed one problem and caused another. Needless to say the customer was even less happy with his work when I showed them what he had done.
Acquaintances doing repairs on the side as a favour rather than a job is another thing to watch out for because some of them are the very cesspit from which dodgy repair stores draw their future employees. Just because someone claims to know all about how to fix a particular problem doesn't mean he knows any more about it than you do. This counts double for laptops; it doesn't take that much knowledge to prod about in a modern desktop case, but servicing a laptop is another story altogether, especially if the work needed requires decapping the screws and removing the case.

1) Despite explaining issues on the phone for a warranty call, I've had the person on the other end still go through a series of 'tests' they want first. Even if unrelated to the problem I've had on had. Encountered something similar to Red_Avatar's story on post 14. No response after powering on, no POST, no lights, no sound (beeping, whirring, buzzing, whatever!), nothing: Try a different monitor was the answer. Eventually, I get them to record the actual issue and can ship the part out.
To be fair, they've gotten better. And my own experience has seen that most issues are something simple like a loose cable, but it does get a bit annoying.
2) My co-worker and I do small-medium repairs where we work, larger/complex/time-consuming jobs are sent to local companies mainly due to time and resources not being available.
A local company decided to call the people on our team 'incompetent at what they [we] do'. But it's a fairly small community here, and we found out the next day. They've since lost us as a customer :)
3) One place had a habit of selling people software that's not what they are after. "Oh, you want to use Word and Excel? Here's a copy of MS-Works instead and whoa now, you're going to need Windows 7 Ultimate to run this beast!". They no longer exist, a different store is in their place who so far know what they are doing and haven't screwed anyone I know yet.
I acknowledge I'm not the most knowledgeable IT guy, and I hate people calling me at night for help. But If I can assist them and steer them away from getting $X00 bills, it's probably worth it.

Ah, that's always fun. :)
My favourite memory of this sort of thing is when my router bricked during a firmware update and the Telecom support guy wanted me to try plugging it in to the wall in another house. Not only would this obviously not get a different outcome I had clearly described to him the distinctive top-and-bottom light arrangement which it didn't display at any time during normal operation (I suspect these lights are mentioned in the manual as its equivalent of the RROD).
It was partly my fault for trying to update their rubbish custom firmware--a feat I wisely never attempted again--but I was surprised that they didn't seem to have any information on hand about something as basic as fault lights for a product they were selling by the thousands to all their broadband subscribers.
Having ISP support consistently insist on walking through double-checking each and every step of the configuration whenever you ring up to find out what the dialup number or SMTP server is is a close second though. :D

Yeah, point (3) of you is a very common thing to happen.
A year or so back, I was in a computer store to buy a cable and was standing behind this guy who had a small business and needed Excel to do accounting. They tried to sell him MS Office 2007 Professional Edition. So the guy went "wow that's not cheap - can't I use MS Office Home?" and they then explained how it's illegal and how you MUST buy the Pro version to be legal. The guy said he'd think about it and left. I quickly paid for my cable and ran out to stop him from getting into his car. I explained to him there's the regular MS Office 2007 which is 20%+ cheaper (which they didn't even offer). It's not a huge difference but it meant saving him €80 at least - he didn't need Access anyway. It just made me shake my head why they'd convince him to buy the extra-expensive version. I've seen the same thing with Vista.

Actually, according to the Microsoft Software License Terms, if he was going to use Office for his small business then he needed at minimum the Small Business 2007 package (he would be barely legal going with the Professional edition depending on how many employees he had). The Home and Student and Standard versions can not be used legally for businesses according to the MSLT.

Weird considering we have the regular version at work and it was sold to us by an official distributor.

You don't have the regular version in a way; most likely you have obtained them through the volume licensing program (VA/KMS/MAK) which means you either have the Professional Enterprise Edition 2003, Small Business Edition 2003, Standard Edition 2003*, Enterprise 2007, Small Business 2007 or Standard 2007*.
* These versions are available to businesses and enterprises only through the volume licensing program.

They sure make it nice and easy :p although you can bet that no-one would care if he had the regular or Small Business version. The Small Business version is even slight cheaper.

While not a computer story: Years back, I had some issue at home that involved calling the state's water utility company, I don't recall the reason why now. They wouldn't help me unless I went out with a metal detector, to tell them where something was.
Good times eh?

Maybe this doesn't belong to this thread, but it just want to share this with my fellow GOGgers: for the first time in my life I'm hoping that I'll get a BSOD, because that would tell me the cause of my recent BSOD problem with 100% certainity: faulty RAM. I'm not an expert with computers so the troubleshooting progress wasn't easy for me, I'm just so happy if I can finally get rid of the BSODs. They've been tormenting me since I got my new rig assembled (my first self-assembled PC so I've been thinking that maybe I did something wrong), which would be about 3 months ago so by now I've developed a kind of phobia when it comes to seeing blue colors (it's pretty unsettling, really). But yeah, didn't take my PC to a local computer repair store, and if everything's gonna turn out fine (and according to your stories) I'm probably not gonna regret it :P

You could of just tested your RAM with Memtest86+ and saved some money on diagnostic.

Oh, didn't even know about that. I did run memtest through BIOS, though, but it failed to find any problems. But I don't even know yet if the RAM stick really was the issue. Thanks for the link, I think I'm running that test right now since I have the would-be faulty RAM installed (that's why I'm waiting for the BSOD)

Best piece of hardware diagnostic software I ever used and bought is Eurosoft's PC Check. V6 and on is now bootable CD rather than floppy.
Memory checks take a good while, but the rest is fairly fast. Can also set to burn-in test mode for short-long durations of testing CPU; RAM; Drives and CD.
Oh, and Michaelleung : Only one thing to do about your NOrton360 : *facepalm*!
I can't say there were any real horror stories in the repair places I've worked in, they were all pretty good. Last one was a contracted-HP repair centre dealing with PCs and Lappies. Dealing with HP on the phone for parts was also very nice (unlike Dell and Toshiba), and they offered to send an official engineer if you thought you could have trouble fitting parts (like say screens and related controlling boards for lappies, which could be painful), but they didn't insist on it.

I'm using Vista. 'Nuff said.
Fail. Fail beyond belief.