|See this for the proper directions:|
What dippncope suggested worked for him, but it won't work for you unless you used Adaware and it removed the spyware wsaupdater.exe.
On the other hand doing that won't do any harm.
There are many different things that can cause your problem.
It doesn't happen spontaneously - something caused it.
Was there some software you installed or updated, or software that did an automatic update such as Automatic Update or anti-malware software, or did you remove something with anti-malware software, just before your problem started to happen?
With that in mind, XpUser's suggestion is more likely to find you a solution.
I'm not 100% sure, but you MIGHT be able to fix this problem by running what many call a "Repair install" of Windows procedure, what I prefer to call a "Repair Setup" of Windows procedure, which won't delete the data you have added including the contents of My Documents, however if anything goes wrong during that and the procedure can't finish Setup, your personal data will still be there but Windows may not work.