When I open Illustrator CS4, and open a new or older document, the windows (action, brushes, layers, pathfinder, etc) are blank. If I close and reopen Illustrator I have a 50/50 chance that they will appear. At times I have had to close and reopen numerous times. Any thoughts? No new hardware or programs added since installation of CS4.(I already uninstalled and re-installed)
Did you dump the preference files before you reinstalled? Try restarting AI with the Cmd(Ctrl)-Option(Alt)-Shift keys held down. Say yes to the dialog box that comes up. See if this doesn't help.
Dumping preferences was done. Restarting as you suggested has opened another symptom - I do not get a dialog box and most plugins don't load. I can use the program but with limited features. I have restarted normally for twenty times in a row and the windows are showing. So we shall see.
Hopefully it will behave itself.