Hello there, Tex
I've been there before, as we all started off.
First things first --
You'll grapple with slackware for a little bit, depending on how computer savvy you were to begin with. Most of the real configuration is done within simple text files -- which can be a plus and a minus.
Your first step towards conquering your problems should be to find a good text editor that you're comfortable with.. Preferably a command line text editor. You'll be able to use that with or without the graphical desktop, which is why I recommend one.
Two of the easier ones installed with slackware by default are joe and pico. Pico has most of the essential instructions on screen, and is very similar to working in notepad. Ctrl-KEY combinations will save your files, etc.
Now then, onto your real problems.
The scroll wheel is an easy fix (that is, once you learn a good text editor).
You should be familiar with the concepts of user permissions, root (which is the ALL powerful user, can do anything, edit any file, etc) and also have a regular user account whose priveleges are limited mainly to running programs and saving/editing files within your /home/user folder.
You'll have to be root to edit most system files.
To fix the mouse wheel, you need to edit the file /etc/X11/XF86Config
Find the section which looks like this, below, namely InputDevice with an identifier like mouse.
Option "Protocol" "IMPS/2"
Option "Device" "/dev/mouse"
# Option "Device" "/dev/psaux"
# Option "Device" "/dev/ttyS0"
# Option "Device" "/dev/ttyS1"
Option "ZAxisMapping" "4 5"
You need to add that line which reads Option "ZAxisMapping" "4 5"
And you should be good to go after logging back into X.
There is a lot of stuff in that file, most of it is commented out, which means it has a # mark in front of it, and X doesn't pay any attention to what follows. You'll see examples of that in my little excerpt above.
Your resolutions are dealt with the same way, in that file. KDE may be able to help configure that for you. Look around your K menu for display options, or a control panel of some sort. I haven't used KDE in a while, myself.
If you want to take a crack at editing it by hand, just post back
Next -- I've had that problem with windows opening outside of the viewing range, etc. This is mostly due to your low resolution. As a temporary fix to this, when it happens, if you hold down alt and click in the window, you can move it around to the point you can hit the ok or apply button.
Konqueror, the KDE file manager and web browser can tell you about your hard drive.
Some command line tools are df (disk free) and du (disk usage.. from the current directory).
You can use df -h (which means disk free -human readable)
The root directory, roughly equivelant to c:\ is simply /
The concept of drives with alphabetical letters is something windows-only. Every disk you use has its own filesystem, and when you put a disk in your drive, you're really mounting it, or sort of integrated it into your root / fileysystem.
For example, when you "mount" a cdrom you can access it at /mnt/cdrom
There are some howtos and tutorials you can search for and find referenced around here that will teach you quite a bit about the filesystem layout and the tree-structure.
Linux is great, once you get used to its differences.
Post right back with any questions or clarifications you want -- I typed this up pretty darn quickly and didn't do much formatting or proof-reading.