Files gone after computer restart and corrupt harddrive

I was browsing internet and suddenly I got message that i need to restart my computer to fix an error and I restarted my computer and after that there was no file and data was corrupted and there were lots of files and i no longer access many files.

now plez tell me how can I restore my computer or I have lost of everything and there is error in my computer for always ? I need to format or I need call compooter engineer. ?

Can you boot into your windows? if no, then your hard drive is corrupted.
No need to call a computer engineer just do the following
1. insert windows installation disc
2. From the repair console, open Command prompt
3. type diskpart and hit enter
4. type list disk
5. type select disk 0
6. type clean

Now you can easily install any OS on your HDD.