Getting sick of these unknown problems

[LOL_NESS]

Hey all, I'm having wierd problems and its starting to bother me. I have a folder with my installs and stuff, well just then i tried to install a counter strike source installer executable, if failed to install, the last time i used it it worked. Everthing for installs doesn't seem to be working, every avg virus free edition i download extracts and comes up with, file is corrupt ,and i've tried it off a few different servers, and different versions, still corrupt! All my installs seem to be corrupting, all my game installs fail, everything i download comes up with a CRC error, wtf is going on with this!? My harddrives have been tested, all pass, and tested ram, pass! Wtf else could be causing this? Stuff i download off the net is failing! I went to download the latest driver for my graphics card, fail! and it 100% downloaded! I never use to have any extraction or crc errors, and i look at the comments on torrents and all are positive, all worked for them, doesn't work for me, WTF?
I'm seriously considerering kicking off this computer for something else. I'm sick of having the same problem all the time, whatever i try doesn't work.
I need someone to have a deep look at my computer, i've reinstalled windows, counter strike source still randomly locks up for no reason, and it runs over 130fps. I'm sick of these unknown problems, all happening all of a sudden, with no warning.

Any help would be appreciated, here is my system specs:
System Name: LOL_NESS
Processor: AMD Athlon 64 4000+X2 Dualcore
Motherboard: Gigabyte GA-MA770-DS3
Cooling: 250mm Side Fan, Exhaust Fan
Memory: 2GB DDR2 667MHz
Video Card: ATI Radeon X1950 Pro 256Mb/256Bit
Harddisk: 2X Samsung SP2504C 250GB SATA2 7200RPM
CD/DVD Drive: LG 16XDVD ROM, CD Burning, Pioneer DVD-RW DVR-212
CRT/LCD Model: Compaq 17" CRT
Case: EZCOOL H-850
Sound Card: Realtek High Definition Audio 7 Channel
PSU: Antec SmartPower 450Watt
Software: Windows XP Home, Windows Vista Ultimate

 

[Kharn]

Have you ran memtest?

 

[LOL_NESS]

Yes i have ran memtest, no problems at all, ran it for 8 hours.

 

[KSoD]

Have you tried a Repair install of XP or to use a Restore point from when you didnt have these issues?

 

[LOL_NESS]

I only just reinstalled xp becasue of the problems, and its still happening.
I did a complete format and reinstall, just as i do any other time.
Sorry about the mention of torrents, i didn't know about that. But its part of the problem i am experiencing.

 

[Kharn]

Is this with any file? or just exes or installers?

 

[KSoD]

I would seriously go thru the Spyware guide. Something is wrong and if MemTest86 didnt find anything the only other thing it could be would be bad sectors on your hard drive causing this.

Have you done a check disk with the /r and /f parameters?

 

[LOL_NESS]

Its with zip files and some exe's that i download, and my exe's that i've kept for a while.
I'v tryed check disk, and when i use vista it sometimes randomly restarts and then comes up with a disk consistency check.

No problems found with chkdsk/r
Whats chkdsk/f?

 

[Jorsoft]

I doubt it's spyware since he already mentioned he's reformatted and these issues are still occurring. Unless it did work okay at first but then started up again shortly after.

I'm thinking maybe the hard disk, then, and it would be best to run a chkdsk /r /f if you haven't already.

 

[LOL_NESS]

What spyware guide mate?

I only just reinstalled so it can't be spyware..

I also checked the disk (took 6 hours) and did a full surface scan with the samsung utility tool.
No errors for both drives.