You can carry out a check disk without booting into safemode. Use your Windows installation disc to boot windows setup, when windows setup detects current version of windows installed, you can shoose R to go into the recovery console, here you can run the CHKDSK command.

If your machine is restarting when you are doing a fresh install, then this can indicate either a corrupt installation source/cd, memory failure, cpu overheating, pci card/s failing or another peice of hardware malfunctioning. In this scenario you would have to remove everything from your case apart from the basics need to do a test install. (VGA,MEM,HD,CD) Unplug everything else.
If your machine still reboots after that when doing a fresh install, try alternate MEM then HD then MB etc....