Computer gone terribly wrong in 5 days.

[JPoPS13]

The Story:
So i bought a bunch of components to build a pc from scratch. Got everything in wednesday afternoon, had it running that night. All was going well, and i was very pleased with the performance (14500 3dMark06, 5.8 Vista Experience Rating)... and then on friday i rebooted after installing new graphics drivers and was unable to post. i removed and reseated the card and all was well again, until today. Vista started acting up on me. Telling me that the sidebar, explorer, indexing and all sorts of things were not responding. So i decided to reformat/re-install vista. Everything was going well upon the first boot after installing again, so i re-installed all of the drivers and rebooted.
The Problem:
My bios couldn't see anything to boot from and wanted my to insert a CD to reinstall vista again but the installer couldn't find the hdd. So i opted the reseat and rewire everything in my case now i get no display when when i power on. tried rewiring and reseating everything again, nothing. When i power on the system all of the fans go full speed (normally they slow down after a second), and no post. Any ideas? i'm desperate!
My build:
DFI Lanparty dk p35
intel e8400 w/ AC freezer 7 pro
2 x 2 Gb OCZ DDR2 800
BFG 8800gts 512mb
phillips ide dvd burner
wd caviar 500gb sata hdd

 

[DaveSimmons]

Try unplugging all drive cables and removing any cards other than video.

If you still get no POST, then given this:

So i opted the reseat and rewire everything in my case

...check that you didn't mess any of the case wires up when you re-wired things.

 

[JPoPS13]

Thanks, but finally after redoing everything a third time it works again, including the hdd. I don't know what it was either. Everything is fine now though

 

[Billb2]

Memory voltage?