Office 2007 basic-Win XP pro

Is there a problem while installing MS Office 2007 on Win XP pro- I give up- may be I’m doing something very stupid or miss something, but I can not install correctly !!! MS Office 2007 on Win XP pro,
MS Office 2007- doesn’t allow me to activate it????
I do not have same problem with installing MS Office 2007 on Wista and Win XP home….
The already installed office 2007 looks like in read-only mode only over Win XP pro- I don’t see any sensible reason, so help….
(excuse my stupid question but I have to manage the problem as soon as possible and don’t have time to read a lot
Sorry once again for the stupid question and thank u in advance