Microsoft office 2000 problem.?

OK, i was at a relatives house and looked to see iff they had microsoft word(don't ask me why i looked,long story)so i see they have it.office 2000.so i then start to search for the disc.after 5 minuites or so i finaly find and ask if i could take it home and try it on my laptop(dell inspiron 1300)so the asnwer was yes and i was chuft untill i got home.i type in all i need but it says the product key is wrong.yet i'm sure its right.i don't know whether its something to do with CAPS or anything so maybe its because the key is already in use

please please pelase help!!

P.S this is what the message reads:

you have not entered a valid product key

please check the number on your certificate of authenticity or the yellow sticker on the back of the cd case

Microsoft office 2000 problem.?norton internet security 2008

The Product Key is already being used by your relative.

What you are trying to do is illegal, try Open Office instead. It is free and compatible with M$-Office.