You can choose to either select the errors to be fixed, or the ones that have affected your system in a negative way. Once you launch the application, you will be presented with a series of three options, one of them being the fast, simple scan, and another which are the more thorough but slower.
PC Repair Tools is an excellent solution for whenever that dreaded problem happens, as it normally solves any imaginable computer error, rendering your PC feel like brand new again.