worm generic_c.zs

Hello everyone and thanks in advance for taking the time to read this post and try to help me. =)

I have a computer which can't access to any anti-virus websites and, therefore, doesn't allow me to even install a program to get rid of the virus which is supposedly making me not being able to connect to these websites (if I knew how, of course). I can't even scan the computer for viruses... I inserted a pen in it and then immediately used that device on another computer and it detected the virus worm generic_c.zs, associated to an autorun file... I am sorry of the language I am using isn't the most accurate, but on the one hand I am Portuguese and on the other hand, computers aren't a subject I really master... =)

What can I do?? How to remove this damn virus? How did it get inside my computer? Any help will be highly appreciated. Thank you!

Su