I actually removed every security software on his PC, (firewall and AVG, McAfee site advisor, Superantispyware free)
Installed the Kaspersky trial.Computer became very slow.
Performed update and worked for a while, then restarted the computer,it did not boot up.
Restored the PC, installed my Norton AV on his PC, running smoothly ever since.
Have to admit, i hate Norton's Sonar policy but otherwise never came across a problem with Norton.

PS: I gave my 70+ day Norton AV key to my friend since i have recently upgraded to NIS 2010