well since you have read my signature you know how to convert your ms partitions into grub speak.
taking /dev/hda1 grub speak is (hd0,0)
hda2 is (hd0,1)
So if you want to install grub into mbr.
the menu items for ms would be
There is not enough info to be sure what your kernel is called in slackware but at a guess
kernel /boot/vmlinuz-(version) root=/dev/hda10 ro
to get the kernel stuff use lilo to boot and write down the kernel and initrd names you find in /boot
or use my trouble shooter to ignore title run C for commands then
kernel /boot/vmlinuz AND PRESS TAB to find options then complete line
initrd /boot/initrd AND PRESS TAB to find options then complete line