Run sfc /scannow
http://answers.microsoft.com/en-us/windows/forum/windows_xp-system/one-of-the-files-containing-the-systems-registry/926cca77-905a-45b3-95c4-50711a6cdc03
http://pcsupport.about.com/od/toolsofthetrade/ht/sfc-scannow.htm
Admin cmd line
sfc /scannow