How to use my PC to fix the os on my laptop? I need to restore my windows 7 os on laptop.

You will need to use the recovery disk for the laptop or the laptop's recovery partition. Most computers nolonger ship with recovery media so you need to make it when you get computer. Coping an OS from on computer to anouther is something this forum dose not support.
If you do not have recovery disk or a recovery partition you will need to buy a copy of Windows or load Linux.