Just over a year ago i decided to buy myself a new pc i bought a P4 3.4GHz LGA775 mobo and all the kit and came across a problem in which at random stages the pc began to lockup. At first i put this down to overheating and changed the Case to a coolmaster one with more ventilation, the power supply and upgraded the cpu fan(asus rocket). In the end i came to the conclusion i had just wasted money it had made no change. I then set out and changed the motherboard to an alternate suitable. the same problem still occured. I then got extremely annoyed and thought it was a cpu problem and replaced the mobo and CPU with an AMD 4.2Ghz dual core and Asus A8V-E SE. I also bought a new 250GB maxtor hdd and installed it as the master and did a full install. The problem still persisted. The only two parts i had not changed were memory and the graphics card. so last weekend i went out and wasted some more money on 2Gb twinX corsair memory and a Ati Gecube X1800XL and still the problem persists. I have pretty much bought a whole new machine over the past year as well as the old one that was still top of the range. I think i can eliminate the old CPU and Mobo as the prob as they are now running in my mates pc happily. I did run a memory test on the old memory and found a problem but the new memory has no problem after a clean test sweep. i am currently running the following 4.2GHz AMD X2 S939 Asus A8v-e SE 2GB DDR 400 Pc 3200 Ati Gecube 256mb X1800XL Pci-e 250Gb maxtor and a 200Gb maxtor (one sata one ide cant remember which) 1 pioneer DVDR 110 and a Plextor DVD rom Coolmaster cavilier 3 case Hiper Power Type R 550w ( i think, im at work so this is all from memory) I have windows xp Pro installed with every update known to man that i could find inc SP2. All graphics drivers are updated and so are the motherboard drivers. Basically the computer will be fine for a while and then all of a sudden freeze. I have recently been playing games on the machine and as i am running it freezes, but when the game kicks back in the charcter has carried on moving. So from this i pressumed possible memory or g card failure but after changing seems doubtful. It makes no difference as to whether your playing a game, watching a film, playing music or typing a document at random intervals the computer still locks.