Well, WinAntivirus isn't something that I would install

http://www.spywarewarrior.com/rogue_anti-spyware.htm

You don't say what OS he is running or what other interactive security products are there. For example, if he has XP SP2 is the firewall activated?

As a general rule you should not run more than one interactive AV, Firewall and pop-up stopper.

I do not see how replacing a DVD drive could affect a security application. All you would do is install a driver, as the DVD management tools should already be there?

I would get rid of WinAntivirus