Ram usage of PC in idle state increases over time?

[KingManULTRA]

I have very little ram to begin with and am wondering why my ram usage in the CTRL+ALT+DEL menu increases over time. It seems to go up in increments of 10 each time up to a grand total of a 30 increase after I've used the PC for a couple of days.

1) I use Windows XP fully updated
2) CTRL+ALT+DEL menu always has the same processes running
3) I have deactivated most unnecessary services according to BlackViper's guide. In addition to the necessary services, I run print services, network file sharing, and local disk management services.
4) I've run AdAware, Spybot S&D, Trojan Remover, Registry Mechanic

Hijack This log:

O4 - HKLM\..\RunOnce: [KB926239] rundll32.exe apphelp.dll,ShimFlushCache

O4 - HKCU\..\RunOnce: [MPlayer2_FixUp] C:\WINDOWS\inf\unregmp2.exe /Fixups

O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll

O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll

O23 - Service: ATI Smart - Unknown owner - C:\WINDOWS\system32\ati2sgag.exe

O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe

[AmIdYfReAk]

Bloat and logging...

i dont know how else to explain it :/

[Foo]

Yep, just bits and pieces building up over the course of use. Most of it would be freed up as soon as something came along that needed the space anyway. RAM is very, very cheap currently, and 30Mb is not worth fretting over.