problem with my HDD and windows 7

well I have windows 7 and I have a 240Gb HDD, which is separated into 2.
one part is 40GB and is called C, that where my windows is installed and the other is 200GB and its called D. i have a problem with D, its always full and I have to delete stuff, so today i counted all the stuff on my HDD and got only 90Gb, so wheres the rest of my 110 Gb? windows shows that I have that 200Gb D drive and its full. can anyone help me to find out the problem?

Hmm if you're sure that your data only accounts for 90GB, then I suggest running chkdsk on the drive to check for bad sectors which might be making some of the disk unwritable.

Open up a command prompt (press Windows Key + R, then type cmd and press enter), type "chkdsk D:" without quotes, It will do a quick analysis of the disk and give you the results, you could copy them here or just have a look to see if it has any spce occupied by bad sectors.