So I had sent my PC to a repair shop for a format, and when I have it back I noticed that some of the games I usually play are running slower than usual. For example, pre-format, my PC was able to handle Left 4 Dead at full detail, and now even at the lowest detail settings it lags and skips like crazy. I've made sure that the drivers are up-to-date (version 275.33), I've got DX 9c installed, I made sure that the anti-virus didn't get in the way by uninstalling it completely before playing, and I even went into the Nvidia Control Panel and set it to emphasize "performance" over "quality", and nothing seems to be working. I'd hate to have to take this back to the shop, is there anything else I can check or do?
Specs: Intel Pentium D 2.66ghz 1 GB RAM nvidia 9400 GT (1 GB) 250 GB HD
UPDATE: So I took the time to run fraps to get an idea of just how bad things are playing, here are the results, I played HL2 for a good 15 minutes, the "Our Benefactors" chapter @ 1024 x 768 resolution and low detail for everything, and no sound.
Frames Time (ms) Min Max Avg 13853 1042360 0 45 13.29
Another test run in another section of the game:
Frames Time (ms) Min Max Avg 6507 898140 0 31 7.245
It's like my video card doesn't even exist
I know my specs are on the low end of things here but I honestly think something's wrong.
UPDATE 2: Reformatted the entire computer again, reinstalled the necessary drivers and tried again, still no change in performance. I'm tempted at this point to think that my GFX card might've failed in some way but it still works as far as the Windows desktop is concerned, I can still surf the web and edit documents, and do other non-gaming related activities.
UPDATE 3: Solved! As per the advice in the answers and comments below I used Speccy and Speedfan to monitor the system temp and saw that it was holding steady at 91 C, so I took it apart and inspected the HSF and saw that the thermal paste was old and cracked and stuff and sure enough when I put it back together and powered up the system wouldn't even stay on, so I replaced the thermal compound and now I'm getting temps of 67-68 C average and Fraps reports the following -
Frames, Time (ms), Min, Max, Avg 8892, 279468, 0, 81, 31.818
And I suspect that the rest of my stuff will work fine now.