Problem resolved. Thanks to suggestion by SjoerdC.deVries in comments. I run the windows color calibration and clicked apply, then restarted Mathematica, and now the orange color has gone:
It looks like the windows 7 monitor updates caused Mathematica to get little confused. Running windows control panel->Calibrate color->Apply fixed whatever the problem was. Here is the button to click on:
original question
I do not know what happened. But when I rebooted my PC, now Mathematica comes up orange colored. I shut down the PC and tried again, it is still orange. Here is screen shot:
I also did a reset. Holding down the ctrl-shift key. And it is still orange colored
I also deleted C:\Users\<user_name>\AppData\Roaming\Mathematica and started, and it is still orange.
All pop-ups and help now is also orange
Also the little + thing on the start of the cell is orange:
I am not expecting someone to just know the cause of this, but may be someone else had this problem and can suggest what to do.
Windows 7 did large update on my PC last night, so it might have something to do with it, not sure. Here is the list of the updates
I did not do anything to Mathematica itself or change anything configuration with it. I just turned orange. No other app I am using has turned orange as well.
specs: Version 10.1, 64 bits, windows 7, 64 bits.
Update
I found something interesting: When I take image of the cell using SEUploader, then it comes up in the image with orange background. While in the notebook itself, it is still white. So SEPloader is picking up the orange color from somewhere. Here is screen shot:
Maybe the above will give a clue to the problem.
per request below, here is the color setting on my PC. I never touch this stuff as I do not understand colors.
But I turned the option above to "use NVIDIA setting" from the "Other applications control color settings" and restarted Mathematica, and it is still orange.
Added result of
FileNames["C:\\Program Files\\Wolfram \ Research\\Mathematica\\10.1\\SystemFiles\\Data\\ICC\\*"] 