screen display colours

Just installed Samsung flat panel monitor.

Am using EXCEL and WORD.

Set resolution as required. All fine except I cannot get colours (eg text and/or cells) to show in EXCEL (WORD is OK) The data is accurate, just no colour on the spread-sheets.

When I transfer the file to another PC all is normal. I have tried all I can think of with the res. settings, Excel settings etc.

Can anyone out there help?
Many thanks
Ron