i have ubuntu on my hard drive partition, and i also have windows vista and win 7. im using the grub bootloader.
i want to install slackware on my computer and replace ubuntu with slackware.
if i run the installation of the iso on my computer and overwrite the ubuntu partition with the slackware one, will i still be able to boot into my other partitions (will grub still work, if not another bootloader will take its place?)?
Slackware uses Lilo, or at least it did the last time I installed it. I think there is an option to install grub with Slackware somehow but haven't been through that process in a long time. If it were me and I had to do what you are doing, I'd install Lilo and just configure it to boot your Windows installs. There should be loads of stuff on the web on how to configure /etc/lilo.conf to boot Vista and Seven. During the Slackware Lilo install, I'm pretty sure it will ask if you want to boot to an existing Windows installation. You could configure it for one and edit /etc/lilo.conf later on to boot the other.
Indeed, Slackware uses lilo, by default.
I've never installed a dual boot between Windows and Slackware, but a quick google leads me to believe that it'll be more or less automagic. The slackbook says you need to select the expert mode while installing lilo.