Quote Originally Posted by Catty1 View Post
If that happens again, restart RIGHT AWAY, keep pressing F8 like crazy when it starts back up, choose "Safe Mode with Networking".

Then download from www.malwarebytes.org and run it!

It is often possible to boot into Safe Mode when you can't start up normally.

Those crazy popup screens are called Rogue Spyware...pretty tame name considering what they do!
I got attacked by one of these at work, and they used the Malwarebytes program to eradicate it.