I Have An Hp Laptop What Do I Do When It Says Operating System Not Found?

Which operating system? This problem is 90% fatal if you're not an expert. I assume we're talking Windows. If so it means that Windows can't read the boot drive (usually C). Either you have formatted the drive or you've caught a virus/Trojan/macro that has formatted your boot drive on the last shutdown. If you have valuable data on the drive you will need to find an expert who is capable of firing the computer up with a PE-CD and can either repair the drive or at least transfer your data to another drive. It may be that only the start files are damaged due to pulling the plug instead of properly shutting down. Other than that, Windows CD in the CD-Drive, start the setup, reformat the drive (everything will be lost), install anew.

Sounds like the boot sector may be corrupt. There are ways to reload the bad files by using the boot disks that you were told to create when you got the machine but as with most people (like me) you probably didn't create them. You may have to call Dell and see if they can send you a set of CDs that will have the original software of that machine (no cost if it is still under warranty).

The bad side to this is that you may loos all of the personal files you have on the machine as it may require a complete reload. There are ways to save these files but it would require you to find boot CD that would also recognize the USB ports and you will need to have a large thumb drive or external hard drive. Then you can can sort through the file structure and pick out most of the files that you would need to save. This is why keeping a backup of your system can be so valuable. And you can't store the backup on you original hard drive like most people do. An investment now can save you bunches of time and anguish later.