It might be helpful if you'd better define what you mean by "background color", and where you expect to see it. Ideally, a screen capture would be best. Use the little camera icon in the web interface to the forum to post images.
If you're talking about any pure white color in a document, it sounds like a problem with Photoshop misinterpreting your monitor profile, though this is the first I've heard of it working in 32 bit but not 64 bit. What profile do you have associated with your monitor? This is done through the Color Management function of Windows 7. Is it a profile custom made by a calibration/profiling device, or perhaps one delivered by the monitor manufacturer?
To reset the colors, hit D, you'll have a black and white colors for Foreground and Background.
Make sure also that you are in RGB mode.
Thanks for the reply, but I have tried that & it doesn't work. The 'white' stays yellowish. I've also tried going into color palette and tried putting in the 'white' numbers... that doesn't work either.
And you do not have proof enabled (CTRL+Y)?
If not, try to look at your color settings, as per Noel's suggestion.
By background color I mean on the sidebar where you can switch from background to foreground, white is not white - it's yellowish. If I start a new document to have a white background, it's yellowish, not white. When I go to Color Picker there is no white. I do not have proof enabled. I've manually entered color settings for white. It shows the correct settings. I have several other programs (Lightroom, Publisher, etc.) all of which have a true white. I also compared all my settings in 32 bit w/64 bit and they're identical. I'm using 32 bit fine, so I guess I'll just keep doing that, but it is a mystery.
Thanks for everyone's input!
What is your current monitor color profile set to? This is done in the operating system's Color Management feature.
You can try swapping a known good profile in for the monitor profile you're currently using to see if it works around the problem. If that helps, your monitor profile will be shown to be the problem.
>> If I start a new document to have a white background, it's yellowish, not white. When I go to Color Picker there is no white.
"whites appear yellow" is a sure sign of a bad monitor profile http://kb2.adobe.com/cps/319/319456.html, the clue is if the Eyedropper tool samples white as 255, 255, 255 and it is not displaying white
the fix would be to run your 'calibrator' routine to build a new monitor profile and target a 6500 kelvin d/65, 2.2 gamma (to start)
also check any monitor hardware settings to be sure they match your target profile (6500, 2.2), if applicable