The first thing to do when you start with N42C-4 is to upgrade Windows as it requires some space disk to process and there's not much free space disk if you haven't upgraded SDD yet. I just upgraded mine up to 1709 version with all patches and it's working great Old windows files will stay on drive during 1 month and will be automaticaly deleted. If you need this space now then here is a solution to kill this folder in a proper way : Step 1: Click in Windows' search field, type Cleanup, then click Disk Cleanup. Step 2: Click the "Clean up system files" button. Step 3: Wait a bit while Windows scans for files, then scroll down the list until you see "Previous Windows installation(s)." Step 4: Check the box next to the entry, then make sure there are no other boxes checked (unless you do indeed want to delete those items). Click OK to start the cleanup.