this is wut u shud have done: Goto a friends house, or if u have another comp, put ut HDD in it as the slave. See if your partitions are intact. If they are, it ur MBR thats screwy or u have a very advanced virus on ur hands. What you would do is pull all info off ur HDD onto ur friends HDD(files u need, not the windows files, ect). OR if you dont have a spare comp, load a bootdisk, once its loaded try to switch to the c drive. if this works (maybe) then type "C:/windows/sfc.exe /scannow. U HAVE to hav ur windows install CD in the drive, this corrects many errors and wutnot in the file system.
If none of these work try redoing your MBR by:
Load ur boot disk, then run the command "fdisk /MBR" and it shud fix it. If all else fails and u cant reinstall windows via ur comp. Put ur HDD in another comp, format it. Scan for virii on the formated HDD AND your friends comp. Then put into your comp and try again.
Other reason windows wont load:
1) ur IDE drive is CENSOREDed
2) ur running Windows
3) ur not running Linux
4) u have a SERIOUS prob with virii in your RAM (in the physical RAM peice) and it load when RAM is innitiallized.
I'm sure other things can cause it. Everything here was written by me, personally from my experience with Winbloze.