Calling all computer repair people on here, my Toshiba is locking up.

I though no way you cann't delete a system file by accident but I did and now my computer doesn't work. It only locks up after a few minutes. I deleted a program and wish I never did. Is there online sites that will help repair or replace a system file? Didn't C-net or another site run a online service that would scan your computer for missing drivers or other important files? My computer is a Toshiba C750-A7286


Thanks for the help.