HOW DO I FIX MY COMPUTER that is about to die???!!?

my computer is about to break down and crash. it probably has like 15 viruses and it was a hassle just opening up mozilla firefox to get on the internet, there is a constant popup from mcafee that says ''your computer is in danger. windows security center has detected spyware/adwar infection. it is strongly recommended to use special antispyware tools to prevent data loss...''

not only that, but my desktop has turned into a black screen with the words ''your computer is in danger''. i have mcafee, but am not really sure how to work it or even if i have all the supplies. some thing called ''brave sentry 2.0'' downloaded and it is removes viruses i suppose, but i honestly have no idea. please help!

i have a fujitsu c series lifebook, windows xp

HOW DO I FIX MY COMPUTER that is about to die???!!?anti virus protection

Windows users might see such a prompt if they visited one of several porn sites that try to exploit a series of Internet Explorer flaws to drop ''Trojan horse'' programs on the victim's PC that directs IE to www.microsofft.org (the URL in the address bar in the picture at right is spoofed with another IE exploit). I'm a little mystified as to why Microsoft hadn't already registered this rather obvious permutation of its trademark (this one was created in February) among several others I found within just a few seconds of searching the Web.