I tried to upgrade my SharePoint server(windows 2003 R2) from standard edition to enterprise to get the 16GB memory， since standard edition only can recognize 4GB RAM.
first try: while in the process of installing enterprise CD2, it requested for something, and the CD doesn;t have it, I clicked skip.
It looks like the installation is successful, but Sharepoint service got problem. SP Web interface cannot be open correctly.
second try: tried to install 2008 enterprise instead of 2003, while i click upgrade, it asked to uninstall some programs first, such as SharePiont. hell no!!!!
3rd try: i haven't not do this one yet, which is upgrade to x64 standard; but i am considering x64 may not suit for some installed services/program...etc.