"hello..i have a lenovo netbook idea pad s10-2 (with windows xp) bought some 2 years back..when i open microsoft office 2007 application it asks for a 25 character product key..i'hv used it several times without entering the key but now it has limited the functionality... i found a product key at the back of my netbook on a label...i think that shows windows in my netbook is a full version(correct me if i am not)...but when i tried entering this it says it is inalid...i downloaded a keyfinder (magical jelly bean keyfinder)...it came with an altogether new 25 character product key...even this one is found invalid....how to restore my product key and functionality of microsoft office 2007 "

You likely have been finding the Windows product key not the Office 2007 one. It's possible that your computer came pre-installed with a demo copy of Office and now, after the demo has expired, you have to buy the license. Best to contact the retail outlet where you bought the computer.
If you have a pirated copy we copy we can't help you.

Exactly! What you had was a 60 day TRIAL version of Office. After 60 days the trial's functionality is limited unless you PURCHASE a license. You may be able to purchase a license for Office 2007 more cheaply since 2010 is out. Otherwise you will have to get 2010 and upgrade.