I'm been working on this problem for over a day now and now I'm stumped. I've read dozens of threads and blogs all over the internet concerning this "operating system not found" problem but none of their problems seem to be the problem that I have. My computer just got extremely laggy and froze into a BSOD (blue screen of death) before turning off and showing me the "operating system not found" message during every boot. Usually when this problem showed up, it turned out to be a hard drive failure, but when I checked my bios, it listed my hard drive as 320gb. (So I'm guessing this has nothing or little to do with my hard drive.) Here are the things I have tried:Safe modesThe "Launch Startup Repair" (ends up with at start up background and doesn't progress any further)The "Windows Memory Diagnostic""Last Known Good configuration"I've transfered the windows 7 .iso to a bootable usb and started up the laptop it got to the Install Now window and when I press that, the window closes and it shows "setup starting" and just stays like that.The only part that seems to be working like it's supposed to is the quick start/splashtop browser option that doesn't startup anything. (It only opens a browser for internet use and no other programs). I'm guessing the next step should be to open up my laptop and see if any of the cables are loose. But after that I don't know what else I could do. Edit- I have just checked and now the operating system not found message doesn't show up. when I start up with regular settings, it just gets to a blue screen and restarts.