Got a Vista MCE remote and IR extender when I bought my Hauppage 1600MCE.
Works flawlessly with Win7 Ultimate RC1 with built in MS drivers.
Is your remote one of the older ones designed for XP MCE (i.e. square green button)? I seem to recall those had problems with Vista MCE early on...maybe its the same thing here?
Yup. That's the one I'm using. Works perfectly in Win7 but not that well in MP (but I always had to make a custom profile for it). Another suggestion: I loved using my 360 controller with MP! It was so awesome.