Windows 7 Hard disk works all the time

Hi WojtekK1902. If you want to avoid a re-install of the system, I would try to create a second profile (new user) on your machine to troubleshoot. This will tell you whether it is something in your Windows profile, or if it is something caused by a system process. If you find that, within a new user account the problem subsides, this means that you just need to do a profile rebuild on your profile (this is much easier than doing a full system re-install). If the same issue occurs when you are logged into another profile, unfortunately the simplest route to take would be to re-install the OS.
Make sure that you backup things like Favorites, documents, and basically anything else that you need to keep that is located in C:\Users\%User%...