Q: Quicktime 7 (which prevents me from using QT Pro) locking up

I have been trying to access QuickTime 7 all day so I can use QT Pro. To no avail, only spinning wheel and it locks up so I have to force quit. I am currently running OS 10.7.5 on a MacBook Pro. Here is what I have tried so far. First I tried to download QuickTime from Apple site for OS 10.6 or later. Locks up. I tried to uninstall all version or QuickTime 7 and reinstall off my Snow Leopard disk. Lock up. I tried to now install the Quicktime 7 for OS 10.6 and later off Apple site again. Lock up. What am I doing wrong. Need help.