There is a worm out and it is in full swing right now. I have heard of many people being infected by it. Here is an article that briefly talks about it.
http://www.eweek.com/article2/0,3959,1208127,00.aspYour computer will say something to the effect that "Your computer needs to be shutdown in a certain amount of time." Something about "RPC". I have not been infected by it so I don't know exactly what it says. I have heard of several people installing the windows patch with no success in correcting the problem. I have found a method to prevent yourself from getting infected though and to find out if you have been infected even if you have not gotten any messages yet.
Prevent for windows xp the main operating system affected:
1. Go to control panel and select "Administative Tools".
2. Double click on "Services" this will open a new window
3. Scroll down and find "Remote Procedure Call (RPC)", double click it. You may have one called "Remote Procedure Call (RPC) Locator", don't choose this one.
4. Select the Recovery tab.
5. Change the "first failure", "second failure", and "subsequent failures" boxes to "take no action".
6. Click apply and then okay. You are now protected.
Fix
1. Click start and select "Search"
2. Search for "Lovsan.exe", "LoveSan.exe", and "MSBlast.exe"
3. If you find any of them delete them and empty the recycle bin on the desktop.
4. Go here to get updates if you have not done so in a while just for future securities sake.
http://windowsupdate.microsoft.com/