Please make sure your computer can see hidden files/folders by doing this:
- Click "Start".
- Click "My Computer".
- Select the "Tools" menu and click "Folder Options".
- Select the "View" tab.
- Under the "Hidden files and folders" heading, select "Show hidden files and folders".
- Uncheck the "Hide protected operating system files (recommended)" option.
- Click "Yes" to confirm.
- Uncheck the "Hide file extensions for known file types".
- Click "OK"
Then, navigate to the following folder:
C:\Documents and Settings\*Your username*\ApplicationData\Microsoft\Crypto\RSA
Please empty the contents of this folder. You should be deleting a folder that has a name like:S-1-5-21-789085689-1013344182-1866953526-1045
Reboot and see if you get the error. Let me know how it goes for future reference.