If I install Office '07 trial edition and want to use Office 2K, will I still be able to?
No, it won’t uninstall Office 2K, although running two versions of Office is not recommended. http://support.microsoft.com/kb/928091
I don’t actually know about the Office '07 installation process but when we installed some Excel '07 “only” products it had the option for standard or custom installed.
We found out that the standard install wiped out Excel 2003 and the custom install consisted of one toggle question where you could choose to retain a copy of Excel 2003 on the machine.
Good to know.