Colored Negative Screen correction

[nos4nus]

I purhased a Indigo iMac with Photoshop, and I must have hit a wrong button somewhere, beause all I can see now is a screen that looks like a colored negative. Is there a way I can correct this. Eventually I'd like to transfer everything from this Mac to my Macbook.

When it first boots up it is okay, but after login when desktop shows it is hard to see.I have pics of the screen if that will help/

Best Regards,

 

[Walrus666]

Hello, try pressing the control-option-command-8 keys at the same time.

 

[nos4nus]

Hello Walrus,

Thanks so much. You have cured my migraine.

 

[Walrus666]

You're welcome.