Computer stuck in reboot loop and has virus

ok my moms computer has a irp hook rootkit and apparently it messed with the safe mode registry and wasnt letting me boot my computer through safe mode. it would go through the list of thing loading then stop and would reboot and would never go though and start normally. before i realized that it was because of the registry, i had set the computer to boot in safe mode automatically. now when i choose for it to start windows normally, it is still trying to boot in safe mode and now i am in this endless cycle of reboot loop. is there any way at all to undo the automatic safe mode boot. pls pls pls pls help me!!!!!!!