About:Blank and Spyware Quake - PLEASE HELP!

Ok i am really hoping some1 can help me with this annoying virus i seem to have downloaded! Its driving me crazy! It has given me three problems...1. I have this new system icon in the system tray, its a little green thing which flashes with a red circle with a line through it every second and occasionnally pops up this box saying 'your computer is infected!' and to click the box to get the available software. 2. It has changed my homepage to about:blank 3. It keeps installing spyware quake everytime i restart my computer, even though i keep uninstalling it!! Please can some one help me. Ive run adaware, spyboy S&D and Norton Anti Virus, but its still here!
Thanku very much,
Ceri.

 

Oh thank u so much! That worked like a charm, no more spyware quake and no more little flashing green wheelchair!! Youve saved me ) xx