I'm running Vista Home Premium on a Toshiba Satellite A200. A few weeks ago, I got three BSODs over 2 days. I have been using my computer for about 4 months without any problems; I haven't installed any hardware recently and since I hadn't unchecked the 'restart automatically' option in my settings, I wasn't able to jot everything down regarding the error messages; one had IRQL_NOT LESS OR EQUAL and another something about ntfs.sys I ran a sfc /scannow and checkdisk just in case. Everything came out clean. About 3 weeks passed without any problem. Just a few days ago, I got a new BSOD. This time I was able to note evrything down. STOP: 0x0000007E (0xc000001D,0x804724E5,0x830779D0,0x830776cc) acpi.sys Adress 804724E5 Base at 80461000 Datestamp 4549adb7 I rebooted. Started running sfc /scannow. At about 20%, another BSOD PFN_LIST_CORRUPT STOP:0x0000004E (0x00000099,0x00054551,0x00000002,0x00007080) Reboot in safe mode. Start running sfc /scannow. BSOD at about 50% PFN_LIST_CORRUPT STOP:0x0000004E (0x00000099,0x00041E7E,0x00000002,0x00004327D) I haven't had time to do anything else. Yesterday my girlfriend tried to boot and the screen just froze on the desktop right after the welcome message. I haven't tried anything yet. Tomorrow I'll try a system restore first to see if it helps any and then run the diagnostics and appz recommended by DonNagual in his Troubleshooting thread I saw from work yesterday that there was a BIOS update for my computer on the Toshiba website but I can't download and install if I can't boot in anything but safe mode, can I? If I can download it at work and put it on a USB device or a CD, will I be able to install it in safe mode? I'm a little hesitant to flash the BIOS as it pretty much messed up my last PC so I'll probably try that if all else fails first. I'm obviously not on my laptop right now and I want to run the whole enchilada before I post minidumps here but I was wondering if anyone had any idea if I should be checking for RAM trouble or HDD trouble first from what I posted here and the scannow trouble... thanks for your replies.