It's actually good if you understand how your PC works before you go into dual-booting (grumble). But here's what happens IMO. Each drive has a part of it called MBR - Master Boot Record. This is where the partition descriptions and properties are kept. If I'm right, MBR is also called "superblock" sometimes (you might have seen some messages about superblock on Linux startup). Now, each partition has a "bootable" flag. Lilo itself either writes its own stuff into the /boot partition or resides on the / partition; but besides, it writes data into the Linux partition's boot sector and places its IPL (which is roughly the boot partition chooser) in the MBR. What Windoze apparently has done (without asking, in the typical Microshit way) is overwrite the IPL with its own DOS stuff. What you need to do is to fully reinstall LiLo (I think that's possible with the Mandrake install CD if you don't want to mess with the command line etc.). You can try "man lilo" for a list of options, but it's better to read more of the LiLo documentation so you understand what you're doing. It's also good to have a nice partitioning programme. You can get a good and free one at http://www.users.intercom.com/~ranish/ . It's DOS-based, small enough to fit on a floppy and can be booted from its own floppy without the need to format /s a floppy in DOS. The site also explains quite well about partitions and booting. With it you can even backup your MBR and then restore it in case of a problem like yours.
