Welcome to Slackware! You will no doubt find Slackware more challenging than Slax, but just as much pleasure once you get the hang of it.
As for the screen resolution, please provide a tiny bit more information about the model of the video hardware you have. Next, the file you need to edit to get stuff like video resolutions and the like, is located at /etc/X11/xorg.conf. You will need to configure the file for your hardware, device driver, and screen/display setup.
If you search LQ here for 'xorg.conf' and '<insert-your-video-device-here>' you will get a great head start.
Also, read the manual page for the xorg.conf file by typing 'man xorg.conf' in a console. It's chock full of stuff about setting up your video config file. Remember, you need to be root to edit the file, and after saving changes, you must restart X either by CTRL-ALT-BACKSPACE or by 'telinit 1' then log back in as root and type 'telinit 4'.
As for the CD player, what do you mean 'should it boot' ?? If you have linux loaded, and want to use a CD, you must 'mount' the device somewhere. With 2.6 kernel, it is much easier to automount CD's and things, but with 2.4 as I recall, it uses hotplug to detect the CD-player, but after you stick a disk in it, you need to mount the CD. Read 'man mount' and 'man fstab' for lots of info.
Basically, you need to make a 'mount point' which is a folder where the CD contents will appear when it is mounted. ALso, you need to edit the file /etc/fstab which tells the machine how/where to mount a type of media. Here's an example:
/dev/fd0 /media/floppy auto defaults,noauto,user 0 0
/dev/hdc /media/DVDROM udf,iso9660 defaults,noauto,user,ro 0 0
/dev/hdd /media/CDROM udf,iso9660 defaults,noauto,user,ro 0 0
These are 3 lines from /etc/fstab. The first tells the machine to mount floppies on /media/floppy, the filetype 'auto' tells the system to try a bunch of filesystems until it figures out what is on the disk. The other options, you can read about in 'man fstab'
The second line is for my DVD ROM device (/dev/hdc). it gets mounted on /media/DVDROM, and the filetypes possible for a DVD are UDF or ISO9660. Same for the last line, for my CDROM (/dev/hdd) which gets mounted on /media/CDROM.
Mounting points ( folders) must exist before mounting any device to them.
I hope this helps you some; likely you will have some more questions if you are very new to this, so please ask away
and good luck!