I have a pentium 11 433mhz. Installed Quick Time but found out
only 2000/XP is compatible...oops (I have ME). Subsequently, I un-installed.
Now every page I access, there's a popup stating I need a QT system extention version 5 or later. Now, since I can't use Quick Time, I don't need this. Unfortunately,
I can't rid this annoyance. Need some info here, please. Still have QT files on drive ( I imagine) and afraid if I weed out, I might have another headache. Any advice would
be very appreciated. Thanks...

If you just recently tried to install QuickTime then try a System Restore:

start > All Programs > Accessories > System Tools > System Restore