If I remember correctly, during that era, Quick-time was a rather mis-behaved program which would bury itself into 100s and 100s of Registry Entries so the Machine Registry is a real mess. You can't delete the files because Quick-time has Registry Entries which are referencing other running system files, etc., etc.
The Best method would be to Clean Install the machine using a Slipstream Copy of Win2K with service pack 4.
Other than doing that, you could try the program below and UN-check ALL Auto Start Entries which reference Quick-time, Reboot and try to remove the files. This will still leave the Machine Registry in a mess.
Also there are File Unlock Programs which you can try like the below but again, the Registry will remain a mess.
There are free programs to (Manually Clean the Registry) but don't know if you want to try that.