If you take a look C Drive in within Win 7 you'll note that there are now two folders for Program Files, vanilla flavour Program Files and Program Files (x86) which basically holds all the stuff for all your 32 Bit games, as far as I know.
I couldn't get TOCA Race Driver Three to work in Vista in any old mode so I have doubts it will work in Win 7. As for Theme Hospital, that actually worked in Vista according to my twin daughters so I'm surprised it won't run in Win 7. Try Win 98 compatibility mode, or even Win XP compatibility mode.
Each time Microsoft have upgraded/changed their OS's there have been gaming casualties, for around the last 15 years, that's just the way it is, sadly, which is probably one of the few areas where a Playstation owner can thumb his nose at us.