Try trashing you Preference file

What Matrixphoto said should work, trash the Preference file.

To re-create the preferences files for Photoshop, start the application while holding down Ctrl+Alt+Shift (Windows) or Command+Option+Shift (Mac OS). Then, click Yes to the message, "Delete the Adobe Photoshop Settings file?"

Best way to do that is while holding down those keys, right click on a PS shortcut, then choose 'Open'.

It will delete, then continue to open and it rebuilds a new one.

Downside, you may have to redo you palette layouts, tool presets, etc.

First, I would locate your actions file [.psp] and other relevant ones, copy to a safe area, then if you lose those on a new start-up, copy them back into the folder overwriting the ones in there. Obviously not the Prefs.psp file.
Close PS first of course and re-start.

Here is list of paths to those .psp files: http://kb2.adobe.com/cps/405/kb405012.html

Use the Windows Vista path, same as W7.

I have never needed to do this, but apparently it's a common fault in CS4 from what I have learnt when searching.

Trev.

Many thanks for the suggestions. I have recreated the preference file for Photoshop before and I did it again this time.... to no avail.
Any other suggestions would be greatly appreciated. I have done many searches and so far have not found anything that has worked.

You may have to do a full re-install

Sorry :(

Yes, like Matrixphoto said, I see you did do a full re-install, but you would need to save the Actions.psp and any other .psp files first [obviously not preferences], then unintall, but go looking for those folders again and totally trash them, since by just doing a re-install over top may not solve the problem since they are still there.

If it behaves good, then drop the actions/other .psp files back into the folder, that way you will have almost everything the way it was.

Thanks again guys... looks like a full re-install it is. It their some program like driver sweeper for video cards that searches out and erases Photoshop files?

hkula, sorry mate, don't know, never had to do it... Google deleting photoshop files after uninstall.

As I said in previous post, I see quite a few references to Tool problems in CS4 over the net/forums.

Trev.