Try booting into the safe modes and see if that fixes the issues of the cumputer
To boot into the safe modes, hold down the Shift when you turn on the computer after you see the bios the screen, then you should see the menu with the safe modes options. Choose the first one.
Then open up the msconfig (type it in the start menu or in Run) then tell me what's in the startups tab
what is the version of the Windows you are running?