sig-->You presume a lot
First off, thank you!!! That is exactly what I was missing. I now have a dual boot.
It also explains why fdisk gave a warning when I tried to make the extended partition bootable. Frustration can make it difficult to see this hints from the system. Anyway, all of this had been following 3 days of trying to get it to work on top of a long string of frustrations in trying to set up windows to be useful.
In case anyone else is having similar difficulties, a few more notes:
1. Win7 won't backup to network drives (which I have), unless you upgrade to professional. It will read/write to them, though from Home Premium (at least) and let you (despite what the msdn board said) assign drive letters to network shares. Same as XP.
Anyway, I copied over my home directory and documents. I also exported my firefox passwords and bookmarks and copied them to the network drive as well.
2. After booting the slackware cd, I mounted a small usb drive and wrote out the master boot record and partition table to it. In hindsight, I should have done that before repartitioning, but worked out OK, except that...
3. I used windows to shrink the big partition size initially. None of the partitions line up to the proper boundaries--none, not even the ones it came with new. This may lead to problems later. Thankfully linux can read all of the partitions
and back up everything to a network drive.
4. The small 100MB partition is the one used to boot windows, so if it's not sda1 (as in my case), lilo.conf needs to updated to point at that partition (sda2 in my case).