Err no need whatever crap software lah.

Just unplug your CDROM / DVDROM power cable from your casing (when you don't use it)

Disable boot via USB in your BIOS.

Change password every 1~2 weeks which consists of 14 alphanumerical + special symbols like !@#$%^&*()_+|"?><

That will make your computer secure from being accessed.

use my mother's method.. keep away modem..

wat if it's not online game? then keep away monitor.. my mum lock it in her wardrobe, + lock room door..

wat if monitor is CRT type? keep away power cable/monitor cable..

easier way? keep keyboard n mouse.. GG.. cant do anything without both..

y do all the hard work?? cz my mum dunno set password.. =.="

all this method are used on my bro not me cz i got my own laptop.. lol..