Free up Hard Disk Space

Use the Disk Cleanup tool to free up space on your hard disk. The tool will scan for files that can be safely deleted.

In My Computer, right click on the C: drive icon and choose Properties. Click on the Disk Cleanup button:
Disk Cleanup will take a short while to scan the hard drive.
Once done, tick the boxes next to the items you would like deleted and then click on Ok to delete. It should be safe to tick all the boxes if you wish:
Windows 10 users have an additional button labeled 'Clean up system files'. Clicking on this button will add a tab labeled 'More Options'. This will allow you to remove old System Restore points and Shadow Copies (backups) of files, which will free up a lot of space.
You'll be prompted to confirm that you want to cleanup old restore points.