my laptop shows that 'operating system not found' when I turn it on.

why

why why?? why?? more details pls, and do u make sure u boot from ur hd not cd-rom or floppy disk where u might put a unbootable disk. good luck

i just turn on my laptop as usual

is there something wrong with my hard drive??

中毒了吧？

harddisk fault!. try to fix the problem with Norton disk doctor

Harddisk failure, could be caused by physical demage or simply a loosen connection. Check the connection of the HDD, take it out and put it back in see if this will fix it.

thx all above.

the repair centre called me said that it is the hard drive fault.

just get a new one. charge me approximately 115 pounds, 40 GB
(my previous one is 30GB)