I know I have a virus or some sort of trojan. I've used Kaspersky, spy sweeper, windows defender, and spybot to look for the virus. they all found a few things but I dont believe that all my problems are gone. On my brothers user just lately the wallpaper has disappeared, the start menu has changed, and Opera (internet browser) has changed fonts and such. It's not only Opera that has changed. His user is just messed up. I recently deleted two installers off of his desktop. I believe one was called WR-1.exe or something like that. I also noticed a suspicious file called retadpu32.exe in my Windows folder. It hasn't replaced itself yet. Lately some of my stuff has been going crazy too. My usually stable Battlefield 2142 has been crashing. Any instructions that dont just point to other instructions would be really welcome. I dont have too much knowledge about all this stuff.
Thanks!

Download AVG

http://free.grisoft.com/doc/avg-ant...

make sure you have no other anti virus running, install AVG, update the software and run a FULL system scan. let us know is what you find.