computer blue screens when downloading

[stu3y123]

not sure what the problem is here, my PC crashes when left to download. it just blanks off then blue screens, its overclocked so i went back in to the bios and selected load optimized defaults. then the pc wouldnt even boot!. i have lowred the fsb and voltage. still the same. any idea?

main parts of the spec
DFI Lanparty NF4 ultra
350mb weterndigital 16mb cache
2 gig balistix ram
Hiper type R PSU
BFG geforce 7800GT
amd opteron 146 cpu

 

[UKDTweak]

Do you have a screen saver set to come on, if so, change it or turn it off. otherwise it sounds like your computer maybe having trouble with going into standby, could be a bios issue? or a hardware issue, check the event manager for errors or warnings.