Not sure if it'd work but you could try booting from your Windows 7 DVD, select the repair options and then load up command prompt. Now just issue the following command: Code: sfc /scannow /offbootdir=c:\ /offwindir=c:\windows
Maybe Daz suggestion will work for you. I tried SFC from the boot menu and it didn't run, said another instance was already running and to reboot the computer. I may have not used the correct switches. Hope it works, keep us posted.