Okay, a few suggestions-
1) When you say you can't boot into safe mode, does that mean the Advanced Boot Options menu doesn't appear, or just that when you select Safe Mode, it makes no difference? If the Advanced Boot Options won't appear, we can try a command in the Command Prompt from the Windows CD.
2) If you have access to another PC, you can try to run antivirus software on the drive you're trying to boot from by removing the drive and connecting to another PC, then running the AV software from the other PC.
3) Try to access BIOS, if you know how. If you can, boot from your Windows disk and run Startup Repair.
4) If you can get to the Windows disk but Startup Repair doesn't work, enter the command prompt and type the following commands, rebooting after each command:
bootrec /fixboot
bootrec /fixmbr
bootrec /rebuildbcd (if the Advanced Boot Options menu doesn't appear, as referenced in suggestion 1)
chkdsk /r
sfc /scannow
5) If none of that worked, and you have access to another PC with an optical drive and internet access, try to download Data Lifeguard Diagnostics, SeaTools for DOS, or some other hard drive diagnostic software. Burn the software to a disk to create a bootable disk, then boot from CD and run the diagnostic software to check for hard drive errors.