Infected with rat virus

Hey,guys as topic says im infected with RAT virus (remote administration tool).
The problem is that it just remain after full format on the hard drive.
I tryed to scan with antivirus bootable disk :
Kaspersky
Dr.Web
Eset nod32
But without success.I've read in forums that the virus may hide in MBR/BIOS.
after following all these I install geek squad webroot on my device. I called the geek squad team and they helped me in removing rat virus from my system.