Hello, it's a bit of a strange story so please try to fallow through. :rolleyes: I will try to write everything what happened from start to finish. Here goes: My friends PC had crashes during gaming or intensive usage. After cleaning a wall of dust between the radiator and the fan of the GPU and running a FurMark stress test it all seemed ok. After a few hours he called me again and said that his PC crashed completely during a Skype conversation and would not get past the initial boot screen. At that point I have tried: Ree set the GPU. Ree set the Ram. Reset the CMOS with the battery. Oddly enough the Bios would not boot up ether. Tried the GPU in another PC, worked. At that point I thought that the power supply could have died. I had hocked up that PC to my own power supply and got to Windows loading screen, however ether nothing would show up after the loading or I would get a BSoD with this message: Driver_irql_not_less_or_equal Stop: 0x000000D1 Bios works, set everything as it should be. What is even more weird that after this I had tried the old power supply and got the same thing as with my own. From here I tied to run the PC with only one stick of ram and switched between sticks. Didn't help. The PC does boot up to Safe Mode. From there I have tried windows restore from a couple of days and tried loading last known good configuration. Did not work. For now I am running Memtest on all the ram sticks and after 2 passes there are no errors. However I doubt that anything will show up as it may be a driver issue or a virus. I am fresh out of ideas and I had hoped that you could shed some light for me before I try any drastic measures (restoring factory defaults) Computer specs: HP Pavilion a6426.sc CPU: Core 2 Duo E4600 Mobo: Asus IPIBL-LB (Benicia) Chipset: Northbridge chipset: Intel G33 Express, Southbridge chipset: Intel ICH9R Ram: 4GB, 4 sticks, PC2-6400 MB/sec (message as PC2-5300) GPU: Asus GeForce 8500 GT 512MB HDD: Samsung 500GB Regards, Ryu.