Excel red button grayed out in XP

After installing Windows XP and then Office XP maybe 100 times I have found that in about 10 installs the red button in the top right corner of a spreadsheet is grayed out or is a small black x in a gray box instead of a red box. I have tried this w/ and w/out the SP’s installed. Reinstalling does no good and order of install in relationship to other applications doesn’t make any difference either. Any suggestions out there would greatly be appreciated.