Never mind what your friends did.
I believe that your hard disk should be OK. Only thing is that it got corrupted because of the sudden power loss.
Since you do not need to recover any data, that makes things easy to get your hard disk back to the factory condition.
Try the HDD LLF Low Level Format Tool HDDGURU: HDD LLF Low Level Format Tool
- free for personal use.
You may use the one with Windows Installer or the Windows executable - that does not require installation.
Depending upon the capacity of your HDD, it may take quite sometime to finish its job of writing zeroes to each and every sector and reinitialising it.
So ensure that your laptop is fully powered for that duration, be patient and do not interrupt it.
Once it finishes its job, hopefully your HDD should come back alive, ready to be formatted the way you like.