So what is it about Lion that is so different? Leopard isn't that old and it supported all the older software I had just fine?
It's not so much how Lion is so different...it's expecting an application from 2004 to work on a 2011 OS. Apple is not a company to keep doing the "same old thing" year after year. They are a VERY innovative company...and with innovation comes change.
Sometimes "change" means we need to update our hardware, software, and OS from time to time. Or...stick with what we have (hardware)..and if so...then be VERY VERY careful updating the OS in case the OS update may make older applications not "runable" (which has happened in this case).
In case you didn't know...there was a OS upgrade in between Leopard (OS 10.5) & Lion (OS 10.7)...and that was Snow Leopard (OS 10.6).
Office 2004 did work under OS 10.6 (Snow Leopard)...but only in emulation...so it was slow. When Lion (10.7) was released...support for the emulation program "Rosetta" was discontinued.
You had a good run with MS Office 2004 (you got something like 7-8 years out of it)...now it's time to upgrade. Of course...you could always reinstall Leopard back onto your computer (to regain Office 2004 compatibility)...but this may be a pain in the butt...and you better have some OS install disks for Leopard!
- Nick