|Try downloading and running these utilities in the exact order|
1- rkill.exe (kills the malware process)
2- TDSS killer (removes unwanted rootkits if found)
run in full scan and fix all it finds, then reboot
Download the above to a thumbdrive or burn to a disc on another PC then use it on the problem one.
I have no idea what 'guard' got rid of the unwanted malicious softwear is???
Some HELP in posting on Computing.net plus free progs and instructions Cheers