My Photoshop CS5 more often than not (but not always), has started , after having opened a file, whichever drop down menu you activate, shows for a split second, then turns into a solid black box, making the program totally unusable. I don't know if this is a Photoshop problem or a computer windows or hardware problem, but I ma very keen to fix it. I did try reinstall CS5 from original discs, hasn't helped. I use CS5 64 bit version 12.0. Would love help on this! Only other maybe related issue is my whole computer goes "system black" on occasions, with a message "no signal" coming up on my monitor. Only way to keep going is to turn computer off at main switch, and start up again. Possible graphics card issue?