Try reseting your preferences:
Close Photoshop. Then hold down Ctrl + Alt + Shift (Windows) or Cmd + Ctrl + Opt + Shift (Mac), and relaunch Photoshop. Respond in the affirmative to the dialog asking if you really want to replace the preferences.
Looks like an operating system thing. It also looks like Windows 7 (I think) so I am not sure, but if you right click the desktop and choose Personalise, you might a high contrast setting turned on, or maybe an easy of access type setting. Or have you installed and are using any third party themes?
I'm sure you'll know what I mean if that's what is happening.
no third party installs.
and yes windows 7 64bit