Computer help please

Okay, so I'm trying to fix my cousin's computer. It has a virus and won't let my update windows defender, and it disabled automatic updates and won't let me change it back. This is basically the only protection he has on his computer, besides some very outdated Norton stuff. It will only let me get to certain websites and if I try to go to the windows update website, some stupid pop-up comes on the screen and if I click it the computer restarts. I can try to update from that site without clicking the pop-up, but as soon as I click update, it brings up another webpage saying your computer is infected with a virus. Some stupid scan thing starts going on the screen and then it says click here to download blah blah to fix this computer. I close out of the window and then it restarts the computer. Finally, my question. He doesn't have a debit or credit card, so would it be safe for me to buy something like Mcafee using my debit card on this computer? Also, do you think the virus would even let me run the program if I bought it, or would it be a waste of money? Any help will be greatly appreciated.Computer help please
No, don't use a card on this comp. It may well be safe, but why run the risk? Try Avast or AVG, they're both free. Or maybe an online scanner if you can't download anythingComputer help please
install and then scan with theseAVG free edition http://free.avg.com/ww.download?prd=afe (read the install carefully or you'll turn on auto scan everyday which eats CPU ifits an old PC)SPYBOThttp://www.safer-networking.org/en/download/index.html Hope this helps :-)
I tried the AVG but it wouldn't let me run it. I guess I'll go with SPYBOT next.
Try running them in safe mode, instead of normal winodws mode
[This message was deleted at the request of the original poster]
[This message was deleted at the request of the original poster]