Hi Leon.
You can put in the disc, and some will run automagically, some will require you to press any key on the keyboard to start the disc, but you will see that come up. Once the disc is started, follow the instructions, if any. It really does depend on what sort of disc it is. If it is a genuine recovery disc, it will probably just go through and lay down a new copy of your operating system. If it is a Windows operating system disc, you may get the chance to "repair" the system.
Please note that you could lose your data if you do not have more than one drive for storage.
Either that, or you will need to take it to a repairer and have it professionally repaired.
Cheers,
Gray.
