When i installed steam i didn't have to change compatibility and it installed fine, i had copied my steam folder (from my vista installation) on to my storage drive prior to installing Windows 7 (to save having to download all my games again), then after stream had installed i pasted the steam folder into my program file (x86) and then verified the local content of each game.
And i've had no problems with playing any steam game (cs:s, 1.6, tf2, fm2009).