Computer keeps freezing

I have XP Home edition installed on my PC but about a month after I got it I noticed that the machine keep freezing after a while. this used to happen on my Me machine as well so I thought it was a Virus because I transfered some files but that machine is now dead. I have a new anti virus software on this machine.

The XP box just hangs up in the mids of an application and occasionally pops up a debug message failure.