W32\gaobot.worm.gen.u-win32\rbot.3eu.worm

click here

Download quick heal antivirus
Click here

downlaod avast antivirus from above link.

click here

download malware removar from above link.
Download these 3 antivirus then install 1 by 1 in computer then update it's definition from internet .
Then scan your computer in boot time.Then it removes all virus.
Make sure after scanning with 1 antivirus uninstall that antivirus then install seconds antivirus.
Then all virus are removed.
Let me know if you need further assistance.
Thanks.

If your anti virus cannot quaritine or remove the virus, the best way is to reformat your hard disk