Storage unidentified problem

i'm in windows 7 OS, before i install it, i allocated 100gig of my storage for my windows 7 and after I selected that partition for windows 7, it became 97gig, and after the installation it became 89.3gig... and after some windows updates and small amount 3rd party programs that i installed, it became 76gig... now guys, i want to know from you some reasons of becoming like this of my harddisk.. its my first time to use this OS and i'm so surprised of this unknown reason of very high consumption of my storage..thanks in advance!

Welcome to the forums!

That sounds about right - Windows 7 requires 16 (32 bit) or 20 GB (64 bit) of space to install. So that plus temp files, swap file and your 3rd party applications will probably add up to your 24GB.

Windows will probably be the most consuming single item of software, so you should still have quite a bit of space after downloading further applications and updates.

Agreed.

And then there's the hibernation file too. If you want to gain space and you know you don't want to use hibernation - then open an elevated command prompt. Copy/paste this command to it then hit enter:

It will free up the same amount of hard drive space as system RAM that you have installed in the machine.