Windows 7 Defragmenting my Pc takes Memory (Go)?

[IV Moony VI]

Hello, yesterday i've bought a used Dell LATITUDE D630.

There's my pc specs:
CPU: Intel® Core™2 Duo CPU T7500 @ 2.20GHz.

CPU Speed: 2.2 GHz.

RAM: 2.1 GB.

OS: Microsoft Windows 7 Home Premium Edition Service Pack 1 (build 7601), 32-bit.

Video Card: Mobile Intel® 965 Express Chipset Family.

I Have 74,4 Go total and after installing Windows 7 Home Premium only 16.0 Go haved been taken after instaling my softwares i was at 17 Go now i have 19.8 Go Taken and 54,5 Go Free.

And today i've used the Hard Drive defragmenter in my pc at the end i've lost like 1,5 Go or 2.0 Go of memory is it normal? :/ I'm sad, i don't want my computer to slow down it's the best i've never had and it's the only one i could buy. :/

And: At wich point does the computer slow down? For an example with my old Pc i was able at the first time to play YouTube videos in HD 720P after some months i wasn't able anymore was it a problem of spaces on my hard drive? The video card or dead pixels?

Thanks for your help in advance. :/

 

[Jimbo22]

Can you post a screen shot of your disc management window?

 

[IV Moony VI]

Hmm.. I don't think you'll gonna understand my computer is in French and the problem solved by itself after an update i've got the momery back , thank you anyway

 

[Jimbo22]

I can translate if need be....but glad to hear you solved it.