Install CCleaner to remove temp files and system junk... if your disk is so filled that CCleaner doesn't install, delete temps manually to make room as follows: Click Start button / type in the search bar: "%temp%" and hit Enter, and delete the files contained in the temps folder.. next type "temp" to open C:\Windows\temp and delete temp files, and next try again installing CCleaner... this program can liberate from a few hundred MBs up to several GB of disk space.
To liberate more space from your C Drive, you can move your folders within the user profile folders to drive F as follows:
Start \ Documents \ right click \ Properties \ Location tab \ you will see a Path to your Documents folder that reads as: "C:\Users\your_user\Documents"... Edit it to: "F:\Users\your_user\Documents"... and press Apply and OK. The Documents folder will automatically move to drive F...
Next browse to "C:\Users\your_user\Music" and again in the Location tab replace the drive letter to F and press Apply and OK..
Repeat with every other folder: Contacts, Desktop, Downloads, Favorites, Links, Music, Pictures, Searches, Videos.