What's Taking Up Space?
Run Disk Cleanup
Run CCleaner Download
Open a command prompt with administrative privileges.
powercfg.exe -h off
Moving the C:\WINDOWS\INSTALLER Directory
The c:\windows\installer directory often occupies several gigabytes of storage.
While Windows does not provide a mechanism to re-point this directory via the registry, you can use NTFS junctions/reparse points to re-point the directory to a different local volume. Re-pointing to UNC paths is not supported.
Add the executable to c:\windows\system32 for easy access
Create the destination Installer folder on the new volume (ie: D:\Installer)
Move all content from c:\windows\installer to your new directory
Make sure to close any explorer windows with these folders opened. Junction.exe requires that there are no open file handles to these directories
Create the junction
junction.exe c:\windows\installer d:\installer