Removing Slackware and install Fedora
 

Currently, I have a laptop with Slackware 14 and Windows 7. Due to requirements from schoolwork, I'm switching over to Fedora to explore that distro a bit, and for the ease of use.

Question is, how do I safely remove Slackware, then replace it with Fedora? Right now, I have a flash drive with Fedora on it ready to go, and I have a program on my Windows 7 that will delete the Slackware partitions, but I'm concerned with the bootloader, LILO. Should I do something about that first? I don't want to make my system unbootable.

You don't need to remove the partitions Slackware is on, just use them for Fedora.
When you run the fedora installer just point it to the partitions Slackware is currently on and make sure you have it format them. That will prepare them for your new install.
As far as lilo goes, assuming you have it installed to the mbr, fedora will install grub2 in its place and you should be able to boot with it as you did with Lilo.