|How are you arriving at this 10GB number? If you're simply adding up the size of the files, you're going to fall way short. Even unhiding the "hidden files & folders" isn't going to show everything. More than likely, you just have too much crap installed on your system.|
Download, install, & run CCleaner-Slim. Use the "Analyze" button at 1st - that will tell you how much space it can clean. It won't actually remove anything until you click "Run Cleaner". If you don't regularly clear out your temp folders & internet garbage, you may be surprised at how much it will find. Get CCleaner-Slim here (last on the list):
You can then concentrate on uninstalling any software or games that you no longer use, & dumping any useless crap you have in your My Documents folder.