Help with new Linux user - system crashing

[Deke]

I have tried various Linux distros over the years and unfortunately although I really want to love Linux and get away from Windows I find it 'easy-ish' to get things working in Windows compared with command line editing in Linux.
Yes I remember command line editing in DOS and it was easy enough once you learned the syntax and so on and I suppose it will be the same in Linux if I wish I had the time to spend learing afresh but, at the moment I don't.
I need an operating system that I can handle even if it misbehaves and I can do that with Windows but, not with Linux at the moment.
I am using Ubuntu (7.10) but, every now and then it simply stops. I can move the pointer but, absolutely nothing else happens on the Desktop when I click on things and I don't know how to reset the system other than to turn the PC off and back on again. I have scoured webpages for a reset but, can't find one - no 'ctrl+alt+delete' nor Windows Task manager to show what might be causing the system to stall. How do you guys go about finding out what has stalled the system. I can't continue to work with an OS that keeps doing this. I have changed the mouse from one Microsoft type to another Microsoft type and now a Trust mouse but, it keeps happening. I have ran a memory check like someone suggested to see if there is any damaged memory but, it is good. I am running a Dell Optiplex GX620 with 2Gb ram and dual core processors with plenty speed and big enough hard drive. Any help is appreciated to get me using Linux continuously. Power to the people!!

[MikeTbob]

Hiya Deke,
You'll love Linux if you can get it to work right, hang in there. I'm not sure what the problem is here but I will try to help you figure it out if you like. Next time you get a freeze up like that, try pressing "Ctrl+Alt+Backspace", this should shut down your X Window system and probably ask you log back back in.
There is a "Task manager" type program for Linux, it's called top and you run it from the command line.

top

I'm pretty sure Gnome (Desktop) has one too but I don't know the name of it. I'm betting the mouse isn't the problem, maybe the Video Drivers. Have you installed any Video drivers for your Video card? Do you know which Video card you have?
Try issuing this command in a terminal window (command line):

dmesg

Now this will spit out a lot of text, you'll have to scroll to see it all, but see if you can find any errors and post them back here.

[dxqcanada]

Depending on the severity of the problem .... ALT+SysReq

Over heating ? Are your fans running via ACPI ?

Your /var/log/messages file may contain some clue.