My opinion still isn't changed but do let me ask this. Did you ever have anything on sda5 or D: as you refer to it? That partition had to be created by a linux installation or purposeful effort by someone.

Your windows installation is on sda3 and has 20.35GB free. Linux is os sda7 and has very little space available. sda5 appears as if it's never been right. Is that the case? Is there anything on sda5 to salvage?

You've got a problem with the extended partition and with a logical partition within it. Unless you have something that needs recovered, my recommendation still stands. I'd do what I recommended and use this to install Ubuntu and allocate the disk space manually if I was you. http://members.iinet.net.au/~herman546/p23.html