I have a Lenovo IBM Thinkpad R40 laptop that suddenly restarts it self and now it cannot boot properly. Every time it boots there it always shows "Operating System Not Found" sentence and it really is annoying and depressing cause I have a lot of illustrations stored in it. What should I do to make it work again without risking to lose my data. I appreciate your help.

Google is you're friend.

Sounds like the bios is messed up, or some of the system files are corrupt.

To see if it is the bios there should be a screen before the operating system boots. It has text saying to press something like f1, or del. Once you get to the bios screen there is most likely a boot option, and just simply see if the drive contianing the operating system is listed. Also if you have a cd for the operating system you can set it as the first priority. Though it might end up restoring the system to factory.

If you have 2 hard drives that was listed in your computer, and you saved the stuff under the secondary it will be easy to retrieve. You could take out the one with the saved files and plug it into any other computer, or just simply restore the system to the first hard drive.

Though how long have you had this laptop? Since most bad computer parts start failing withing the first 2 months, depending on how much you use it.

I see, thank's Sid. It's about a couple of years, anyway thank you for the solution I'll try it.

you're drive's dead... you should buy and install a new hard drive and install windows... or any other OS you want...

Actually I tried my hard drive from another laptop and my hard drive is not dead.

Before jumping to a conclusion like >>5 suggests, do try the simple solutions first.

A funny one I've encountered is this: do you have any USB devices plugged in before starting up? It might be searching for your hard drive on that. Although I think the earlier solution would have addressed this, unless you didn't know what you were doing.