I have mentioned about this very long time ago, but this thing still exist. So CCleaner is set to delete QTPlayerSession.xml from this folder/path: C:\Documents and Settings\<user>\Application Data\Apple Computer\QuickTime\. But if you delete that file, some QT settings are restored to DEFAULTS (in case you have changed them). Those settings are stored to that QTPlayerSession.xml file.

Here's a sample of the content of that file:

<key>QTPrefsFullScreenRGBCol</key>
<integer>0</integer>
<key>QTPrefsGeneralAutoPlay</key>
<integer>1</integer>
<key>QTPrefsGeneralHideEmptySel</key>
<integer>0</integer>
<key>QTPrefsGeneralMRUListLimit</key>
<integer>0</integer>
<key>QTPrefsGeneralOpenNew</key>
<integer>0</integer>
<key>QTPrefsGeneralPauseOnSwitch</key>
<integer>0</integer>
<key>QTPrefsGeneralShowCC</key>
<integer>0</integer>
<key>QTPrefsGeneralShowEqualizer</key>
<integer>1</integer>
<key>QTPrefsGeneralShowHotPix</key>
<integer>0</integer>
<key>QTPrefsGeneralShowTC</key>
<integer>0</integer>
<key>QTPrefsGeneralShowTCAbsoluteFrames</key>
<integer>0</integer>
<key>QTPrefsGeneralSoundBack</key>
<integer>1</integer>
<key>QTPrefsGeneralSoundFront</key>
<integer>1</integer>
<key>QTPrefsGeneralUseHighQual</key>
<integer>1</integer>
<key>QTPrefsOTHFullScreenPresMovie</key>
<integer>3</integer>
<key>QTPrefsSTDFullScreenPresMovie</key>
<integer>3</integer>
<key>QTPrefsWSFullScreenPresMovie</key>
<integer>3</integer>

BTW, here's my previous post about this same subject - no aswers: http://forum.piriform.com/index.php?showtopic=6248&hl=

Yes, i had that problem too. Now i just disable the 'quicktime player' (in 'multimedia') option in the cleaning part of CCleaner.