When u install windows 7 or earlier version, sometimes, one or more of your hard disk partition doesn’t appear and is not accessible from my computer. Don’t think your partition is lost or the files on your partition is gone forever. TO get your drive partition back, just follow these steps :
Right click on my computer – select Manage – Chose disk Management – Now you’ll see all your partition and drives listed there in the right pane – Find and identify the drive which is hidden or not shown in my computer – Right click on the partition – chose add drive letter and path / change drive letter and path – assign a new drive letter from the drop down box – Ok
You are done. Now you’ll see the hidden drive or partition listed back in your computer window.
Tips: Use disk management tool as mentioned about above to extend and shrink hard disk partition size.