you do not have permission to shut down and restart this computer

"you do not have permission to shut down and restart this computer"

Every now and then, I get a lot of hits from Google on the above keyword. Since I have encountered this problem once with my home PC, and another time with my office laptop when I reinstalled Windows, I felt it is important to type this entry. I thought that most people would know how to fix the problem by now, but if I'm getting so much hits on this keyword, I know I'm wrong.

What is causing your Windows machine to prompt that error message?
You have been infected by a computer worm called SASSER.

How do I fix the problem?
Download the W32.Sasser Removal Tool at Symantec.com It's very effective stand alone tool clean up the infection.

How do I prevent it from happening again?
Many viruses and worms floats around on the Internet, so you need to learn to protect your PCs.
1# Don't open any unknown/unexpected files or emails. That includes common files such as .doc .xls .jpg and many more. Erotic.jpg might sound interesting to you, or you think reading FungShui2006.doc would be nice... think again.
2# If you are using Windows XP, turn on your Firewall. It doesn't slow down your system performance.
3# Run system scans at least once a week. You don't have to purchase expensive anti virus or anti spyware software. Free ones like AVG and Ad-Aware does the job well.
4# Keep your system up to date with the latest security software patches. (Meaning, run your automatic updates!)

Learn more about Sasser from Symantec and Microsoft.

Remember, protect your PC. Prevention is always better than cure.