Dual install

Yes it can and it doesn't need a separate drive. just make sure to backup all of your settings and templates, and use a separate location for your templates. I believe that 2008 will convert them, and then they won't be able to load in 2007.

I thought I was dual installing 2009 with 2008 by copying 2008 and updating the copy. However I was not able to run 2008 after that even though the folder is there.

Had I realised that 2009 would not run stably in the environment that ran 2008 well, I would not have updated.

You never want to 'Update' major releases of software. You can run both side by side, but to go from 2008 to 2009 best practice is to uninstall

I was running SW07 and SW08 earlier without any issues. And now I have SW07 and SW09 running on the same machine without issues. Just keep two different folder/location for setup, toolbox, template files and any other related setting/files.

Deepak Gupta SW2009 SP3.0 SW2007 SP5.0