I know I'm being a bit greedy but I wanted to install WinXP (for my girlfriend), SuSE 9.0 and Slackware 9.1 for me.
I did this on a 38 gig h/d like so-

NTFS(winxp) - 2 partitions (7 gig and 14 gig)
SuSE 9.0 - 1 10 gig partition and a 1 gig swap
Slackware 9.1 - 6 gig

My problem is, rather than use LILO as Slackware proposed I thought I'd stick with GRUB that was installed with SuSE.....however....it doesn't work. Windows and Suse are recognised but Slackware fails to boot, I've set the drive up in YAST but it wont boot from the GRUB screen. Is there anything I can do about this? Would setting the boot manager to LILO make any difference?

probably your grub configuration (/boot/grub/menu.lst) needs some tuning

could you post details ? (partitions, grub config, etc)

good questions and

Did you create boot disks to get into slack?

Did you start to install lilo?

Any messages you can see on boot up such as li l lil lilo or grub errors would be appreaciated