Sometimes Blaster's warning pops up so fast it's not readable. I'd suggest you check for a virus first. Blaster can have other slightly less predictable effects as well, if you're on a network. It makes the network traffic go haywire, for starters, it can overload the internet connection until everything starts timing out, and it can also cause all the XP machines on a network to shut down simultaneously. There are at least two online antivirus scans available for free, if your machine will stay running for long enough. www.sarc.com and click on the 'check for security risks' graphic part-way down the page. The same site also has free virus removal tools for specific viruses. There's also http://www.pcpitstop.com/antivirus/default.asp. (PCPitstop also have a scan for spyware and a bunch of other useful stuff).