Windows 7 windows 7 startup loop

From my experience, this will be a difficult problem to resolve in a pleasant way and may have only one (unfortunate) solution.

To cursively see if you have a hardware problem, try to boot from an emergency start-up disk (did you happen to make one? If not, you can easily make one from another similar system running Windows 7). If you can boot from the emergency start-up disk, run chkdsk on your boot drive and see what it says (chkdsk is on the emergency start-up disk -- the command is "chkdsk <boot-device>:", like "chkdsk d:"). If your boot device is the usual "C:", it may be named "D:" temporarily or another letter depending on your configuration. Any errors detected by chkdsk? If so, run it again with the "/f" switch and it will try to correct the problem(s). Then, do it again to see if further problems were detected or created (not likely, but it happens). The success of this depends on they type of problem(s) it finds. If corrections are make, try to boot normally, and if necessary, in safe mode. If none of this works, it is likely that you have a corrupt file that is used during the boot process. Most likely, the only way to fix this is to reinstall Windows. But, before you go that far, let us know what you find.