I have XP on my desktop computer.
I have used Ubuntu on my laptop computer without real problems and am aware of using commands in a terminal.
Partioned XP to accept Debian on my disc.
Purchased a 3 DVD disc set of Debian 4.OR3 to install on my desktop computer.
Ran disc 1 and Debian installed without any desktop. Desktop applications
must surely be on the disks 2 and 3 but I have no way of insatlling from them.
When I run Debian (GRUB loader) there is no gnome or other desktop only a screen terminal. When I boot the menu.lst has several boot alternatives including XP. But it will only boot successfuly if I select
kernel 2-6-18-486(single user)
When say I apt-get istall kde (I am connected to the net) it starts to do so but when it asks if I want continue and "y" it asks for media change asks to insert disc labelled 'Debian GNU/Linux 4.0 r3 _Etch_ -Official i386 DVD Binary-1 20080217-11:31' in the drive /cdrom/ I tried with all 3 discs but nothing happens and thy are not read?
Help

Did you select "desktop system" when you installed cd 1? Try editing this file:

# gedit /etc/apt/sources.lst

Remove any references to cd's or dvd's. The file should look like this:

deb http://http.us.debian.org/debian/ etch main contrib
deb http://security.debian.org/ etch/updates main contrib

Save the file and run # apt-get update. Then try installing KDE.

Do as wernerz said, only to make it cleaner just comment out the CD-Rom entry by prefixing the line with a # sign. This helps if you ever have the need to put it back (seldom if ever)then you just un-comment it and your done. In case you didn't already know you will have to be root as shown by the pound # sign in wernwerz post.

What happens when you try to boot another boot entry in grub screen, e.g. Windows?
'Debian GNU/Linux 4.0 r3 _Etch_ -Official i386 DVD Binary-1 20080217-11:31' is the one, you used to install your Debian system. What happens when you insert it after the media change query? Are there any error messages?