Problem with Loading on GTX 285

Hey people, been a while since i've actually been on here helping people out but, now im not so sure about the problem i'm having.

Build:
Gigabyte UD3R
GTX 285
HDD Seagate 500gb
PSU 800w kingwin
CPU e8500
Xigmatek s1283 Heatsink
Centurion 590
1066 CL:5 OCZ reapers


Now The computer was just fine running at 3.8ghz since last october and just the passed weekend I turned it off, came back the next monday and turned it on everything was loading fine till it got to the Windows loading bar. When it got to that point then screen acted on loading the desktop but, just turned black and did nothing. At first I was like ***! my GPU is going bad? how?

I put in the gigabyte recovery disc and it booted up but, it took about 30seconds on the windows loading bar and its gradually slowing down to 15seconds now on the loading bar but, what is causing these problems? Is it still the GPU?

I tried the safe mode when it started happening, it wouldn't load it in safe mode either, it posted alot of lines about the computer then it was stop and sit.

Hopefully it's fine now but, with the slow loading, i'm going to test the gpu/hdd/ram and see what I can get out of it, surely its not the gpu because it's running games just fine.