Crash on login

I restarted my computer the other day and when it goes to start the login screen and does the windows jingle it crashes halfway through the tone before the login screen has a chance to show up...
it doesnt give a bsod or an error, the screen goes black and my monitor says no signal.
i noticed my videocard had dropped its driver the other day and so i reinstalled it. i figured that might be the problem so i uninstalled everything that i had installed in safemode that vista would let me since the last restart before things went bad. unfortunately it didnt make difference. i can access safe mode and safe mode with networing fine. havent tried command prompt because i cant think of anything id need it for in vista that i know how to do.
i also checked the event log and there werent any critical events in the past seven days.
im lost here

specs
amd phenom II x4 940 @ 3.0
seagate 250gb @7200 rpm x2
seagate 320gb @7200 rpm
gigabyte cd.dvdrw combo drive
asus cd/dvdrw combo drive
xfx geforce 9800gtx black edition
mushkin xp ascent w/evci pc8500 4gb
mushkin pc8500 @4gb
vista home premium sp1
foxconn a79a-s mobo

 

<<<<<<<<<<<EDIT EDIT EDIT>>>>>>>>>>>
I actually reinstalled 182.50 nvidia drivers over the previous 182.06 drivers not deleted them as it says above. the drivers arent supposed to be loaded in safe mode anyhow.

speedfan is currently logging temps of

gpu 234C (i just noticed this temp after i checked what was going on after the crash on boot, it was previously running around 30c idle)
temp1 29C (sb?)
temp2 31C (nb?)
temp3 -128C (pretty sure there is no sensor for this one)
HD0 29C
HD1 29C
HD2 31C
core 28C

also, i did run a stress test after this build, which happened about two months ago and memory hd gpu and processor all passed

vcc3v 3.42
vcore 1.36
vram 1.90
vchipset 1.16
+5v 4.88
+12v 12.14
vcc1.5v 1.65
vsb3v 3.38
vbat 3.36

 

Have a look at this: http://forums.majorgeeks.com/showthread.php?t=35246

 

i cant install the debug utility because safe mode doesn't allow windows installer to initialize. i have no viable restore points, the vista repair utility is saying that there are no problems on boot, so apparently it's a problem that occurs immediately after boot while loading the full OS, which explains why i can use safe mode and not normal mode. so far the memory diagnostic has given me nothing. im running a triple pass in extended mode. ill rerun chkdsk with /b afterwards, but thats the end of the line for me. i aint that smart

 

There's also

CHKDSK C: /f/r

It'll do more.

 

so i rebooted in low resolution mode and it worked fine, but on a reboot after changing resolution back to 1680x1050 and vista forcing me to install updates it crashed again. i really hate windows sometimes.

 

Did you manage to run chkdsk?

 

i ran chkdsk after the 2nd failure and then retried low resolution mode. i actually saw the windows logo this time so im assuming it fixed a little bit of something, but i cant for the life of me figure out what. next move is swapping video cards and removing all drivers unless you have a better idea. im just poking at stuff at this point and seeing if it works.

 

Did you run this one? Run it again?

CHKDSK C: /f/r

Also: scannow Vista: http://support.microsoft.com/kb/929833

You have of cause used SUPERAntiSpyware and Malwarebytes' Anti-Malware?

Or what about these:

Last Known Good Configuration Vista: http://windowshelp.microsoft.com/Windows/en-US/help/cdb4c0dd-5698-4197-b906-d6a6d413621d1033.mspx
System Restore Vista: http://windowshelp.microsoft.com/Windows/en-US/help/517d3b8e-3379-46c1-b479-05b30d6fb3f01033.mspx

 

chkdsk /f/r ran twice
i tried to run sfc /scannow but i had trouble getting into safemode last night

ive run antispyware antimalware antitrojan and antivirus

last good config gave me nothing

system restore is not an option because the os cannot find a viable restore point.

 

further issues. safe mode as well as normal mode are now inaccessible. i rewrote the mbr with bootrec /fixmbr and then ran bootrec /scanos to find that the vista disk can find 0 operating systems. unfortunately i have three and none of them can be found. after restarting again GRUB has now taken over my mbr. im pretty sure that this is bad, or at the very least, not good.