The Mac OS will look for the most recent version of Quicktime. If you find the folder where that bad QTX is located. you can rename it, and the OS can't find it.
Better still -- since you may overlook some snippets of QTX code located elsewhere -- you may want to consider uninstalling QTX and QT7, then reinstalling QT7.
Thanks Szalan - I done this and no change.
Thanks Dave - Same with this Although i do think your right about Quicktime X code being still there as when i first tried to instal 7 it said QTX was there but I deleted it with Appzapper so other traces were deleted. Do you know of where code can hide?