Windows Won't Start

I turned on my computer this morning, and all I got was a black screen and the rather unhelpful message "Operating system not found" in little white letters. Is my PC trying to tell me that my hard disk has crashed?

When you turn on your PC, the first thing it does after completing its Power On Self
Test (POST) is to scan your hard disk for something called a master boot record (MBR), a pointer to a program on your hard disk that tells your PC which partition contains your operating system.

This error message means that your PC can't find Windows XP's boot information, because the MBR is corrupt, the entry for Windows in the MBR is absent or corrupt, or any of a half-dozen other reasons. But don't panic the solution is often a simple one.
First, eject any disks from your PC's floppy and CD drives, and then reboot. Some computers check these drives for boot information before moving on to your hard disk, and display the above error message if no boot records are detected.

If that doesn't help, determine whether your PC is detecting your hard disk at all. During the self-test, your PC displays a bunch of information about your system, including details about the processor, memory, and hard disks. (Many new PCs display a large logo while this is happening, but you can usually hide the logo and display this information by pressing the Esc key.) If the screen blows by too quickly, or you don't see any hard disk information, enter your system BIOS setup screen, and peruse the information there.

If your hard disk typically identified by manufacturer and model number is not listed, your PC is not detecting it. There are about 50 things that can cause this problem, but it's often nothing more than a bad data cable. Crack open your PC's case, and make sure the IDE, SATA, or SCSI cable connecting your hard disk to the motherboard is firmly attached at both ends. If the problem persists, replace the cable with a brand new one. You could also unplug every drive other than your hard disk (e.g., CD and DVD drives, Zip and tape drives, etc.) to see if one of them is causing the problem.

If your PC is detecting your hard disk but Windows still won't load, fire up the Windows Recovery Console (WRC) and attempt repairs there. To get into the WRC, insert your Windows XP CD in your CD drive and turn on your computer.

After Setup loads all of its drivers, press the R key to start the Windows Recovery Console. When the WRC starts, you'll see a screen titled "Windows NT™ Boot Console Command Interpreter." If you're asked "Which Windows installation would you like to logon to," type the number next to your Windows XP folder (usually 1…c:\Windows), and then type your administrator password. Once you've logged in, the WRC looks and feels a lot like the Windows Command Prompt (a.k.a. DOS), but it supports only a handful of DOS commands.

At the prompt, type dir and press Enter to display a listing of the files and folders in the root folder of your hard disk (usually c:\). If you see a bunch of garbage characters or you get a strange error, stop immediately and take your hard disk to a data recovery expert.

Otherwise, if the listing looks normal (i.e., you see the WINDOWS and Program Files folders), type fixmbr and press Enter. Then type fixboot and press Enter. When the two commands finish, press Ctrl-Alt-Del to restart your computer and see if Windows loads properly.

If Windows still won't boot, your hard disk needs more help than I can provide.

If your drive contains any valuable data, try a recovery utility such as SpinRite or, if you don't want to risk doing more damage, take it to a data recovery expert and hope for the best.

Warning: Checking your hard disk for signs of corruption is a crucial step. If you continue and attempt repairs on a corrupt drive, you may irreparably damage data that otherwise might be recoverable. Windows Setup actually provides another, easier- to-use feature (an alternative to the WRC) entitled "Repair an existing installation," but it's a poor choice because it doesn't let you check for corruption before effecting repairs.