If your computer is making grinding noise it is most likely that you have problem with some of your fans or hard drive.

Usually your computer has a CPU fan, power supply fan (case fan) and video card fan, you should ask a technician to open your computer case and inspect those. If they are all ok then it is very likely that your hard rive is failing. First thing you should do in that case is to back up all your important files. Once that is done please free some space on your hard drive and defrag it. If possible replace to avoid loss of files and programs.