Debian Locks-Up Whenever I Use SU Privileges

[Red Savina]

I recently installed Debain to hda7 (7.6GB) on my Dell Dimension 2400 (1GB) using the network install CD ("debian-6.0.3-i386-netinst.iso"). The installer dsecided my IDE drive was a SCSI device, so actually it is sda7. The installer had difficulty finding a video mode to match my monitor, but after 6 or 7 reboots it found a suitable mode, and there were no hicups after that.

I manually partitioned sda7 as mount point for "/", filesystem: ext3, label: Debian, mount options: defaults, space reserved for superuser: 5% (the default); sda6 - filesystem: swap. The following software was installed: Graphical Desktop Environment, Print Server, File Server, SQL Database, SSH Server, Standard System Utilities. GRUB2 was installed to the MBR.

Everything seems to work fine until I do something that requires SU privileges. Then everything except the mouse pointer locks up shortly thereafter, not instantly. For example, I needed to edit grub.cfg so I could boot DOS on sda1 and the two copies of WinXP on sda2 and sda4 (pre-existing). I was able to save the edits, then it locked-up. My only recourse has been to hard shutdown. The File Browser says I have 3.2GB of free space. Also, I cannot login as root, though I can use the root password to gain SU privileges anytime I want (for a few seconds or more).

The system identifies itself as Debian "Squeeze". The press release @debian.org says that "Squeeze" has something to do with education and classrooms. I just wanted the latest stable release. This is my first attempt at Linux. Please help me diagnose the problem. Thanks!

[Paul Komski]

Instead of
edit grub.cfg

have you tried
sudo edit grub.cfg

and then entered the relevant su password? (the cursor does not move during such entry)

[Red Savina]

Actually, I entered "su", then the root password. Then I did "edit grub.cfg". As I said before, "I was able to save the edits". GRUB2 boots the other three operating systems just fine. The problem is that Linux locks-up, seemingly shortly after invoking SU privileges, but I'm not positive that is the cause.

I can't login as root at the initial login screen, but I have no trouble doing so in a terminal window. Maybe this is normal. It always accepts the root password. For example, if I try to view sda1 in File Browser, I get a pop-up asking for a password to mount sda1. I can view its contents for a while, then everything locks-up except the mouse pointer. I have to power-off manually.

[Paul Komski]

Don't know abut Debian but in Ubuntu it can be done as per http://www.liberiangeek.net/2011/03/...natty-narwhal/

[mjc]

What desktop manager are you using? Gnome?