Have you tried using 'disk clean-up' and de-fragmenting your computers hard disk drive ?.
Follow the steps below to perform each operation.
To delete files using Disk Cleanup
The following procedure cleans up files associated with your user account. You can also use Disk Cleanup to clean up all the files on your computer.
Open Disk Cleanup by clicking the Start button . In the search box, type Disk Cleanup, and then, in the list of results, click Disk Cleanup.
In the Drives list, click the hard disk drive that you want to clean up, and then click OK.
In the Disk Cleanup dialog box, on the Disk Cleanup tab, select the check boxes for the file types that you want to delete, and then click OK.
In the message that appears, click Delete files.
Disk Defragmenter
The Disk Defragmenter utility consolidates files so they occupy space more efficiently. The end result is that files are accessed faster, improving your computer's overall performance.
"Defragmenting" can take an hour or more, so it's best to do this when you don't need access to your computer, for example during the wee hours of the morning.
Click Start, click All Programs, then click Accessories, then System Tools, and then Disk Defragmenter.
Select the hard drive to be defragmented (usually Drive C).
Click the Defragment or Defragment disk button. If a User Account Control message appears, click Yes.
(Optional) Repeat Step 1, and then carry out Steps 2 and 3 for other hard disks that appear in the list.
[Source: https://ttlc.intuit.com/questions/1899610-clean-up-and-defragment-your-hard-drive-windows ]