Antivirus question? help!?

I think my computer has a virus. The startup button has this --

lsass.exe

it just wont be deleted.

I don't have any antivirus. Please help me erase the said virus.

P.S. I don't know where to get a free antivirus. I couldn't afford the high cost antiviruses.

Antivirus question? help!?suzuki

I use these programs to clean friends computers.

It helps speed up the system and usually

works every time unless there is some very unusual virus on the system.

They are all free programs.

1)Get spybot search and destroy, install, update and run.

http://www.safer-networking.org/en/index...

2)Get avgfree anti virus, install, update and run.

http://free.grisoft.com

3)Get windows defender antispyware, install, update and run.

http://www.microsoft.com/downloads/detai...

4)Get avgantispyware, install, update, and run.

http://free.grisoft.com/doc/download-fre...

5)Get Avira antivirus, install update, and run(dont use both AVG and Avira, pick one)

http://www.avira.com/en/pages/index.php