How do you fix missing or corrupt boot sector?

The easiest way is to put your operating system disk in the computer and do a repair.

If you have XP, then it is a nightmare and to long to explain, your better off, doing a install

of the OS, then making sure system restore is on and making a restore point.

But if you want to try and you have XP, below ill post a repair for the boot.

http://pcworld.about.com/magazine/2111p196id112479.htm

This is for recovery console.

http://support.Microsoft.com/kb/314058

Vista and Windows 7 are very easy to fix the MBR, you just put in the disk and it will repair it for you.