If you've recently updated to Windows 8.1 you may have noticed you have significantly less space on your machine than before the upgrade. Little tell-tale sign is the presence of a Windows.old folder – which suggests that rather than installing a series of updates, 8.1 actually did a full install and migrated your 8.0 installation.
You may not be able to manually delete the .old directory and temporary directors – the best way to clean up is to use the in-built disk clean up tool. Right click on your system drive, select properties, then click the disk clean up button:
Next, click the "clean up system files" button:
This will display more options such as ""Previous Windows installation(s)" and
"Windows upgrade log files".
If you are feeling particularly brave – you can also remove your System Restore points and Shadow Copies (do so at your own risk – if you decide to – ensure you have a back-up /recovery plan in place):
Hopefully with those simple steps you can reclaim ~10GB of space.