Captainsolon

Hello

I am new at this site but from what I can see and from what I heard you guys are doing a very good job.
Ok enough with the flattering.
These are my specs:
DualCore Intel Core 2 Duo E8200, 2666 MHz (8 x 333)
Asus P5N-D (2 PCI, 2 PCI-E x1, 2 PCI-E x16, 4 DDR2 DIMM, Audio, Gigabit LAN, IEEE-1394)
Motherboard Chipset nVIDIA nForce 750i SLI
System Memory: 4GB (DDR2-800 DDR2 SDRAM)
Display Video Adapter: NVIDIA GeForce 8800 GT (512 MB)
3D Accelerator nVIDIA GeForce 8800 GT
Monitor : LG L1900J (Digital) [19" LCD] (180146633)
PSU: Hyper 530 Watt
2x 120 mm case fans

I have 50 of these machines as I use them as client pcs for an internet café. I have them for three months now.
Now the problem that I am having is while a costumer is playing a game (mostly LineAge II, WOW, Call of Duty 2 & 4, Track Mania Nations, Need for Speed-all the latest ones- Warcraft II Frozen Throne, Command and Conquer 3 Generals) they get a black screen and the computer must be shut down in order to make it work. Some times but rarely the screen turns pink or gray-white. On the LG display I get a message that it does not have a signal. The graphic card and the display are connected with a DVI cable on both ways.
Running Everest Ultimate Edition I get very normal temperatures form all the components. Actually that was my first guess and I placed a second fan to make the air circulation better but still no result.
What drives me crazy is that the same pc will be used for hours and hours and never presents such a problem and on another day it will crash every time I run a game.
I have two machines shipped to the tech-department of the shop that I bought them and they changed the PSU to a new Hyper at 600Watt and still the same. They changed the graphic card and we are still waiting. I have installed on all of the pcs Deep freeze so there is no chance for virus. On various pcs I installed the new nvidia drivers after I removed then with all the possible ways but still no solution. One more thing that I must tell you is that not every pc does this. I have some machines that have not stuck at any time but these machines are very few.

I would appreciate if you can suggest to me a solution in order to make them work.

Thank you for your time.

emosun

Hmm , hyper is not a good psu brand , all of these machine have hyper 530watts? 530w despite the brand , is too low for any 8800 setup. Should be 600w or higher with 26 amps on the 12v rails. Should also be good brands such as thermaltake's toughpower, corsair , antecs trio , or silverstone.