I have a brand new computer with Photoshop CS 5.5 64bit installed on Win 7 Pro 64bit and my graphics drivers are up to date.
When I open photoshop and I click on a file menu drop down (e.g. File) and I move the mouse to hover over "Edit", the Edit menu doesn't drop down. That's not a big deal, but annoying.
However, when I create a new file, I cannot use the drag select tool as it wont register my clicks on the canvas screen. I cannot right click and I cannot resize the canvas.
I've spent the last few hours trying to troubleshoot this including reinstalling Photoshop, running the 32bit and 64 bit versions, deleted preferences, uninstalled DisplayFusion, ran in compatibility mode, had a graphics programmer remote in and disabled openGL. None of those things have worked.
Adobe forum: http://forums.adobe.com/message/4352886
The strange thing is that it works perfect once every twenty or so times I try it.
Any ideas? Reinstalling Windows (this is a fresh install of Windows 7 Pro) is the absolute last resort.
-- Update --
I couldn't answer my own question but the problem was that I had synergy running as a service on the computer. Stopping it made Photoshop work.