For Office 2004? No. In fact, the trial version doesn't convert at all--you
would need to remove it before installing the retail version.
NeoOffice is free, though.
http://neooffice.org/
If you only wanted Word, AbiWord is also free:
http://www.abiword.com/
If you are a student, by any chance, MS Office is heavily discounted for
students, but still a chunk of money.