After Installing Slackware rather than reboot do these following instead.
0.Before starting the install run the command network and it will automatically enable the network for you, so if you want to run network install you can do that too.
1. After the installation is finished it will ask you weather you want to shutdown,reboot or shell and choose the shell option
2. You will be dropped into a shell. chroot in to your install by running
chroot /mnt
3. Edit /etc/inittab file and change the default runlevel to 4 so that you can login to GUI desktop.
4. Create a local user by running command adduser
5. The adduser command will take for of setting up your user account.
6. If you feel the need to add your user to extragroups run the command
usermod -aG $GROUP $USER
7a. Edit /etc/default/grub to add the following line
GRUB_DISABLE_OS_PROBER=false
to allow os-prober to detect your Windows OS.
7b. Instead of Lilo you can install Grub as your boot manager in the same chroot run the command
grub-install /dev/sda
grub-mkconfig -o /boot/grub/grub.cfg
then reboot you should now have logged into your GUI desktop. After you have logged in you should first create a local bashrc. Slackware doesn't ships with a bashrc. Here is a sample and a very simple bashrc
# If not running interactively, don't do anything
case $- in
*i*) ;;
*) return;;
esac
# Bash version check
if ((BASH_VERSINFO[0] < 4)); then
echo "This .bashrc file requires at least Bash 4.0"
exit 1
fi
# Make sure if the history file is deleted...
if [[ ! -f "$HOME/.bash_history" ]]; then
# Recreate an empty copy so history apps don't show errors
touch "$HOME/.bash_history"
fi
# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
if [ -f /usr/share/bash-completion/bash_completion ]; then
. /usr/share/bash-completion/bash_completion
elif [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
fi
# Make sure 256 color terminals are enabled
export TERM=xterm-256color
export use_color=true
PS1="[\D{%d/%m/%Y}-\A] \u@\H-\W:-\$"
PS2="[\D{%d/%m/%Y}-\A] \u@\H-\W:-\$"
REFERENCE:
https://docs.slackware.com/howtos:slackware_admin:grub_on_first_install
https://docs.slackware.com/howtos:slackware_admin:installing_with_gpt_without_uefi#grub_2