Vista - hl2.exe has stopped working

Ok, so I'm sure this problem has popped up more times than people can count. Anyhow, Team Fortress 2 always shows this message when I try to start it. It never even loads it. Just begins then stops. I've tried everything Steam support said to do. I've tried the security workaround. I've disabled UAC and DEP. I've moved the folder to 'Common' instead of username. I've deleted Steam and reinstalled everything. I've enabled msinfo32.exe. I've repaired WMI. I've done just about everything people have said, and still nothing. Are there any other fixes people have heard about? I just want to play Team Fortress 2 lol.
I'm running Vista x64 Ultimate Edition. Processor:Intel Core 2 Duo E6600 @ 2400 MHz Physical Memory :2048 MB (1 x 2048 DDR2-SDRAM )
Video Card :Nvidia Corp NVIDIA GeForce 8800 GTS

Hello essysin2,
Has it ever worked or has it been like this from the start ?.

It has worked before. It's happened once before but i believe i fixed that by turning off DEP.

Well the first obvious question is, are all the drivers up to date ?.
Also have you tried running it as an administrator ?.
There is another thing you could try, a No Cd patch, it's worked for me in the past.
Good luck and keep us posted.

i believe all the drivers are up to date. to be honest ive had this problem for about 8 months now. I keep trying to fix it periodically, and nothing ever happens. I've ran it as the administrator. A No Cd patch? for what? TF2? I suppose I should clarify that TF2 has never worked on my computer. Half-life 2 does. My mom bought me just TF2 at best buy for christmas. My friend can run it on his computer (which is the reason I'm trying to fix it so badly, because I remembered how much freakin fun it is). Therefore it has to be something to do with my computer.

I would check your drivers first. follow the link and choose option 2.

Drivers - Download NVIDIA Drivers

You may have tried this, also check your screen refresh rate/resolution is correct.

Possible fix for launch and scoreboard crash - Halflife2.net Forums

Just tried it. Got nothing. also tried the couple other solutions presented there. I'm trying to find more now. I'm downloading the new driver now. Well, I'm waiting for it to start, doesn't seem to want to do that. But maybe that'll fix it.

Fingers crossed lol.

nope. didn't do it haha.