Nod32 install fails to boot

S~!

I have a friend who installed the Nod32 trialware after hearing me rave about it. Unfortunately he can not get the machine to boot up after, is there perhaps a known issue with nod and xp64 which he is also running?

What would be some good first steps to take in diagnosing the problem? I plan to have him do a system file check tommorow, can someone throw some input our way - I hate to have him give up on it. He was previously using Avast and has gone back - I would like him not to think Nod32 is a bad program.