old MFC shell extension updatable?

I just crawled out from under a rock (ok that should fend-off the comments about my old software).

I've got a shell extension I programmed in VC++ with some MFC, my version of Visual Studio is really old (v6).

My shell extension used to work fine (great actually) on Win2k and XP, having avoided the3 whole Vista thing, I now have a Win7 box and notice my shell extension doesn't work anymore.

Can anyone tell me what is required to get an XP type shell extension to work in Win7? and if I can do it with my old version of VC++.

Define "doesn't work anymore".