I am looking for someone possibly verify what I think I found.

For versions 2504 and later, clicking the configuration option to uncheck 'enable file deletion from hard drive' permanently changes the way that PD9 works for the worse. PD9 becomes very non responsive after an edit or two. It may take 10-30 seconds to respond to a mouse click.

For versions up to 2330a, checking or unchecking that box has no visible effect on the program speed.

If the program is completely re-installed, it works until that box is unchecked again. But once it is unchecked, re-checking that box does not change performance.

Also, for versions 2504 and later, I have seen performance change once the list of 'confirmation' items in the preferences menu is opened, whether or not any boxes have been unchecked or checked.

This may help explain why a 'reinstall' can help, and why some reinstalls do not. It may not be a windows registry problem, but a configuration file problem within PD9 that gets jumbled. It can also explain why the program may work for a while - and then not.

So, if there are any takers on the proposal - completely remove PD9, set up the computer with latest drivers, etc as recommended, then install the 2701 trial version. DON'T OPEN THAT GEAR ICON OR TOUCH ANY OPTIONS - except of course to tell PD9 where the files to edit reside. Then do a couple of your favorite edits to see how the program works.

Then, pull up the 'configuration' dialog box via the gear icon or preferences menu and Uncheck 'enable file deletion from hard drive'.
Then do those same edits and see if PD9 works the same.
Then recheck the 'enable file deletion from hard drive' box and see what happens.

The file used here to test operation is a 15Mb/s, 720p/59.94/5-1 384k mpg file about an hour long.
I7-950/X58/6GB