Virus cut internet access & .exe's from running

I can't get online to reactivate NIS 2009 because I've a virus that won't let me access the internet except for one site: Antispyware Soft (antispy-guide.net/purchase?r=70.10&pgid=1). Its so bad, I can't even get online w/ this computer w/o unplugging that computer from the router.  It interrupts internet access, & closes .exe's and TaskManager as soon as they're opened!  Any help short of a full reinstall of Windows would be REALLY appreciated!