Ok well first off, the hex code CCCCCC is a grey, not a cream. It's the lightest grey in the Web Safe palette.

Second, if this has just started happening as of late, i'd be concerned that the problem "might" be with either your graphics card or monitor acting up... or starting to go. Check your monitor settings to make sure they haven't been altered by accident. But this actually sound like a Photoshop problem, and not a system display problem.

Photoshop 5.5 lets you setup specific "colour profiles" (under the File menu), but unless the Gamma settings have been played with, your colour palette should not be altered in the way you're saying it is.
If the colour in your palette "looks" correct to you, but filling a canvas with it produces a different shade/tone, then i'd think the problem lies somewhere within the colour profile you have set for Photoshop.

Also...
If you're using PS 5.5, then try looking under the VIEW menu for the "Preview..." setting. Try switching to "Uncompensated" or "Windows" and see if that helps.

Unfortunately, not knowing anything specific about your system, about the only helpful thing i can really suggest is to refer to the PS Help files to get a better understanding about "colour profiles", and how to make the most of them or edit them.

Good luck,
Mark (aka theKeeper)...