Hi all, Have been reading a number of threads regarding crashes/blue screen for a few weeks now before i posted my own problems. I have a Pent 4, Asrock P4S61 mb, 160gb hd(IDE), socket 478, sis 661fx chipset, 2x512 mem sticks running XP Pro. I have no extra cards inserted. The computer is about four years old and has been running with no problems until a few months ago. I started getting random restarts then blue screens, I tried a number of options to no avail. I ended up buying another identical hd. Swopped them over installed XP etc etc and it seem to be okay for a few days them the random restarts started again and over time the blue screen started again. I got a memory checker and it showed no problem with either stick (tried them one at a time and both together). The most unusual thing was that when i ran a system diognostic programme (Everest) it never restarted/blue screen even when i went online!!! I would run this test for a few days with no problems? This programme would also show 'no battery' on it's display when there is a small battery in there, assuming it's the one they are refering to(does this need changing?). The system is not overheating either. I've also cleaned out the cobwebs and checked there is nothing loose. Bottom line is now, I've wiped the HD and installed XP again. I've got the original memory stick in and the original drivers loaded no other programmes and not online, so basically excactly as i purchased it thinking it should run okay now? Not a chance, I switch it on and run the XP tour to test sound and picture. Runs for about 20mins then bluescreen! Sometimes 'driver_irql_not_less_or_equal' is shown on screen. I'm trying to work out how to post the mini dump. There is one thing that is different to the original spec and that was i had a 'phut' sound from the system and my monitor went down, change fuses and no go, so i have a different monitor. I'm considering getting a replacement mother board and swopping all the bits over. By the way i'm not very computer savvy, can just about do the basics. Sorry i've gone on a bit but i thought i'd give as much info as possible! Cheers BBJ.