simply means that your operating system has issue swithin its regsitery files, so only thing i can suggest is the following.
start>run> SFC /SCANNOW you need to do this with the original system's OS disc, ie the disc it was installed with. as this will then check the files to what is on the disc and try to correct any issues.
save any files to another computer by taking out the HDD and install as a slave to a working system.
then format and install a fresh copy of the OS.
Mathew lisett, December 2007