|I can't see the rest of the message. |
Normally that location is a way to put files or shortcuts or programs available to all users. All users is not really a user but a holding spot for (you guessed it) all users.
Might install MS's security essentials or other software to protect and check your system if you don't already.
Consider looking at removing old un-needed apps or using disk clean up to free up space. Defrag may help a bit.
If all else fails then consider re-loading the OS from OEM disks.
"The era of big government is over," said Clinton 1996