Windows using too much RAM

[gogero]

i3 2310m 2100MHz 4GB RAM 1333 Mhz
Geforce 525m 1Gb. 640 GB HDD
Windows 7 Ultimate 64bit, BitDefender internet security 2012
The PR is better?
http://goo.gl/KMOls
Tried disabling antivirus, some programs to no avail. The games run well Witcher, Deus Ex, Far Cry 2 - Max-High settings.
The later one i must notify it's a tablet. So what do you think?

 

[sminlal]

Sorry, what's the question?

 

[13thmonkey]

you'll tend to find windows uses as much ram as it needs to.

 

[sagitttaa]

Well, I'm surprised. It's a bit of my post in another forum (not very helpful).

My system
DELL Inspiron 15R
i3 2310m 2100MHz 4GB RAM 1333 Mhz
Geforce 525m 1Gb. 640 GB HDD
Windows 7 Ultimate 64bit, BitDefender internet security 2012

I have a problem - when I'm installing something (from iso file mounted via daemon tools or power iso) or UPLOADING via dc++ my RAM usage gradually reaches almost 100% and computer becomes unresponsive (I can barely type this post). After the task is done, RAM goes back to normal, but computer remains a bit laggy for a while. Task manager shows that all processes use 5-20% CPU and about 1GB-1.3GB of memory (normal behavior when Windows idle) . But what uses other ~2.5GB I have no idea. Tried disabling antivirus, some programs to no avail. The games run well Witcher, Deus Ex, Far Cry 2 - Max-High settings.
Screenshot http://tinypic.com/r/6nwfhx/7

I think there's a problem when my computer tries to read from hard drive and stores everything in RAM - don't know why. Is this maybe hardware fault? Any Ideas?