virus problem (blaster or variant?)

Hello! I believe my browser was hijacked by www.enjoysearch.info and I ran avast to find 4 infected files. I then discovered that when I start up my computer, I get a message that says that the computer needs to shut down and a clock shows me that I have less than a minute remaining.

I was wondering what I can do about it and if avast has a newer database that would catch this problem because I have the newest update, yet I still have the problem.

I thank you for any assistance and I hope this will be resolved!

See this post, please.