help, please

Sorry, i posted this under software and did not get a response in a few days. I'm looking for an anser, please help. thanks.............Hi, it has been a while since I needed help, but now I do. I'm running an older machine AMD 3500+, asus A8V deluxe mb, 2 gig of ram, ATI 1650 video. with serial ata drives. I'm using window xp pro 64 bit. I have 2-3 hundred gigs of TV that i'm trying to edit out commercials. I have the win movie maker that comes with the os. I crashes all the time. I am trying to edit a smaller clip ( approx 2 hrs ). some of the clips will be like 7 hrs long. I'm not trying to do anything really hard ( i thought ). any ideas ? thanks. ( they were recorded from cable tv on an ATI tv tuner card. if that helps or matters and they are in MPEG2.