"BOOTMGR is missing, Press Ctrl+Alt+Delete to Restart"?

My computer broke (again) yesterday, and I was wondering how to fix it. I tried re-starting it after it froze, and then when it did it came up with a black screen that read: "BOOTMGR is missing. Press Ctrl+Alt+Delete to Restart." I click Ctrl, Alt and Delete and it re-starts, but it comes up with the same screen again. This has happened before, and last time I had to take it to a computer shop to get it fixed, and it took forever. I was wondering if there was a quicker way? I heard that if you use your Windows CD or something it works. I don't want my files deleted though... But yeah, any help appreciated. (: