video card and standby issues

I have a Geforce FX 5700LE 256MB video card clocked at 300/480 (a bit overclocked, but just so you know I did set it back to factory settings). My power supply gave way last Thursday. No biggie. The fan inside the thing was humming like an Abrams tank anyway. So my warranty covers a new fan (more powerful, something to support the newer, faster video cards). I test it out at the computer shop and after the Windows loading screen, the monitor turns black and eventually turns off. We tried a few more times and the same thing happened. Great, probably a power surge messed up the Windows installation. I reformat (I had to disconnect my slave drive so Windows wouldn't install into it). I got everything setup how I like it and I start playing Counter Strike: Source. After a few minutes the game crashes and on the desktop my mouse starts to lag, I reboot and the screen goes black after the Windows load screen, just like before. I got into safe mode so I know it has something to do with the video card. And no, it's not the video card drivers because I switched back to older ones that worked a few weeks ago with no problems. Anyway I boot up Windows today and low and behold, it boots up with the video card drivers, like normal. I'm afraid if I start playing a game that requires extensive use of the video card I might have that problem again. Is there any way to check if the video card was damaged? I wouldn't know exactly what to look for.

Second problem. Before the reformat when I put the computer on standby, it would shut everything off, the fans included. Now it doesn't. I checked in the Device Manager that no device can take Windows out of standby (having this checked under the keyboard or mouse causes the computer to keep the fans on during standby, at least on my nForce2 mobo). I have suspend to RAM in the BIOS on. Any ideas?

For the first one, I assume you changed the power supply unit, right? The twxo things I can see is the video card getting loose somehow, so you just need to take it out and put it back in to check, and the second is to check the video card fan (if it has one), if it broke and you start asking a lot from the card's gpu, then it just poops itself when it overheats.

For the second issue, I have no idea, I never use stand by on this computer, because I can't get out of it.

First proplem i'd suggest doing the following.

Run 3D Mark 2001 or 2003 and see if the system locks. If it's a problem with graphics card that should course it to crash. Also take your side panel off whilst it's running so you can see if the cards fan is going round and if it's going at a fast enough speed to keep the card cool.

If all seems ok, i'd suggest removing all the PC's components and re-seating them, including the CPU.

As for the second problem. I'd suggest you don't bother using stanby mode. In my experiance it's twitchy as hell. Just turn your pc off if your leaving it.

Yup, the GPU fan is cooked. Hopefully my warranty covers it. Oh, and I bet Windows still thinks the fan is running so it won't put itself on standby. Thanks for the help.