My PC (a HP running XP Home) will no longer start as it normally does ever since I switched it off last time (when I only printed a document). When I switch it on, the XP logo loading screen appears, but then I get the white text on black options to start Windows normally, Safe Mode, Last Known Good Config etc. No matter which I select, the PC always immediately restarts and goes back to the XP logo and starts again. Pressing F8 and using the options there results in the same. I've tried putitng the XP Home CD in, but it doesn't boot from that. Ocassionally I get a blue screen with "UNMOUNTABLE_BOOT_VOLUME" and some 0x0... codes. What should I do? Thanks.