Microsoft Office lock左

琴晚我用word做Mail Merge..
用完都冇問題..
隔左1陣諗住用word做其他野..
點知打吾到字..
全部功能都灰哂..
下面寫住:
This modification is not allowed because the selection is locked.
之後我開ppt同埋Excel都系打吾到野..
有冇人可以教我解lock?

ps.我用Microsoft Office 2007 (應該系Home果個version) - 人地上網down的
中有,我個Microsoft未activate.
吾知呢點關吾關事呢?
因為我1開果陣d功能有色的,不過佢即刻彈舊野出黎要我activate
我禁左cancel之後d功能就灰哂..
其實裝左Microsoft Office之後每1次都彈出黎,
我每1次禁cancel都冇事..
Please help me!
Thx so much!