RAM doesn't seem to empty, even when I close windows

Please do the following:

To check for a virus please visit one of the following sites for a free online virus scan. Even if you a virus scanner installed, this one gives you a second opinion, and it will be up-to-date which yours might not be.

Symantec:
http://security.symantec.com/sscv6/home.asp?j=1&langid=ie&venid=sym&plfid=23&pkj=TBOWYHGBYNCJEIMXQKC

Trend Micro:
http://housecall.trendmicro.com

If you do not currently have and antivirus program install you can try AVG from www.grisoft.com – it is free.

In IE go to Tools -> Internet Options -> and delete Files and Cookies.

To check for and remove any Spyware or Adware that may be installed on your machine, download and install Adaware and Spybot. Then update each program before scanning. Fix ALL problems found by either of the programs. You may need to reboot and have the scan run at startup. Run it again to make sure all components have been removed. There is also an Immunize in feature in Spybot that should be enabled to protect against some installations of Adware/Spyware.

Ad-aware and Spybot:
http://spywareinfo.com/downloads.php?cat=sp#det

If you have Kazaa, it has to go. Uninstall through ADD/REMOVE PROGRAMS in Control Panel then use Kazaa Begone to remove it completely. Kazaa is full of Spyware and spreads viruses. All file-sharing programs cause a multitude of problems and promote illegal sharing of information.

Kazaa Begone:
http://www.spywareinfo.com/~merijn/downloads.html

Then post a Hijack This Log to have someone analysis it for further cleaning/recommendations.

Hijack This:
http://www.spywareinfo.com/~merijn/downloads.html