Hi - I seem to have acquired something that most people are calling "ransomware", although it has not asked me for money. My computer starts up, the generic blue desktop shows up briefly, and then the entire screen from bezel to bezel goes white, with a short message in the upper left that says "Please connect to the internet....".
I took it upon myself to try a simple fix from a Microsoft tech website, and I booted as Administrator in safemode and reverted to a System Restore Point approximately a week before the white screen first showed up. The machine now boots normally, except that I receive an error message late in the startup process:
"avguard.exe has encountered a problem, and needs to close. We are sorry for the inconvenience".
There is information screen about the error signature, but it is composed entirely of blank fields or zero values (ex. ".0.0.0.0")
Is there more that I should do? It's an old machine with Windows XP home, SP3.