Are there command line options for the setup.exe?

[alpaca]

You should search your registry after "Rome - Total War" and remove all keys and "folders" that you find.
Do this by pressing on start->run, entering regedit and clicking ok
Then press Ctrl+F, deselect "Search whole string only" and search for "Rome - Total War"

[Kif_Kroker]

thanks for your help. i'd already tried that but there were so many of them I got bored and used a registry cleaner. I seemed to have developed a problem with 3d max as well so to cut a long story short I've reformatted the damn thing.