OMFG! I have THIS FREAKING VIRUS THAT'S INFECTING MY COMPUTER AND I CAN't GO ONLINE! PLEAS

Okay, before I had this green desktop of a blue sky, Now, I have a black desktop that says ''You're computer is infected. Microsoft security Center detected a virus blah,blah,blah Install antispyware to prevent data loss''

AND whenever I log onto my computer, a red button with a white ''X'' appears on a taskbar saying that my computer is infected. And this thing on my computer called ''Brave-Sentry'' keeps popping up and scanning my computer and it said that they're are like 100 threats and that I have to pay to get it fixed. For some reason, I can't seem to get online so I can't download any virus protection. Is there any other way for fixing this without paying or going online????COULD SOMEONE PLz HELP ME HERE????? THANKS A LOT!

OMFG! I have THIS FREAKING VIRUS THAT'S INFECTING MY COMPUTER AND I CAN't GO ONLINE! PLEASE Help!?network security

It's no virus infection.. this is called spyware a.k.a. malware. it is unwanted and it tries to get you to buy stuff, tracks your online doings, and downloads unwanted crap to your computer. You would need to get online to get software like the ones below:

Ad-Aware SE Personal:

http://www.download.com/Ad-Aware-SE-Pers...

Spybot - Search %26 Destroy:

http://www.download.com/Spybot-Search-De...

AVG Anti-Virus %26 Spyware (2 programs):