XFree86 4.0.3 with Voodoo3 2000 and Virtual Resoluitons

I have successfully installed XFree86 4.0.3 and have gotten it to work with
my Voodoo3 2000 card. But, I can't get the Virtual Resolution to work. I
have settings in my XF86Config file. For example:

DefaultDepth 24         # I don't bother with the other depths
SubSection "Display"
    Depth 24
    Modes "640x480"
    Virtual  1200 1000
EndSubSection

But, it doesn't allow me to scroll around the desktop like in 3.3.6
Do I need to install Glide? I am using Slackware 7.1 - does it have Glide
installed. I hope so, because I cannot find it on www.3dfx.com, and
ftp.3dfx.com no longer exists. If I need Glide, where can I get it now?

I really need to get this to work. I am visually impaired, and I need to
see things at "640x480" but have lots of desktop room to work with.

Any suggestions?