Z-9 locks up

Here's my setup, an old Dell Inspiron desktop, 2ghz Pent.duo, 2 gig ram, replaced XP with Z-9 (yeah that old). I am using it as a HTPC, or that's the plan anyway. So far I'm just streaming Netflix, and a few other internet move channels, will be replacing the DVD with a Blu-Ray, adding a surround sound, and installing an infrared universal remote. But before I go any farther, I have a slight problem that needs to be fixed. There are times that I am maybe taxing the CPU or RAM, like when turning off, or starting a movie, starting a web browser, or something similar. That it will just lock up, and the only thing I can do is to press the power button and do a hard shutdown, then reboot. The mouse is still responsive as far as movement, but I can't click on anything, and any program etc... that is currently starting up, will fail to load, or fail to load completely. For instance the program window border is loaded and visible, but the desktop is still visible in the middle, and that's where it stops.

Now my question is, I know there are several diagnostics I can run to pin down the problem, would you be kind enough to give me a few diagnostic programs/cli commands?

Thank You again for all your help.

Robby

Robby > You need at least 4gb.[ RAM ] for your project.
Your system is grunting barely I bet...with just 2 Gb. [ RAM ]
A Graphics Card with more than 128 Mb.[ Memory ] for perform better with HD
Example : BluerRay = 1Gb + UP !!!! >>>>>>> Nvidia GeForce-210.....Nvidia GT-240

Also better install Z9 lite.

I use Zorin 9 Core on the following machine.

model name: Pentium(R) Dual-Core CPU E5400 @ 2.70GHz
MemTotal: 3063212 kB

And I'm not really using that much of the machine.

Code:

$ free -m
             total       used       free     shared    buffers     cached
Mem:          2991       2247        744        217        151       1186
-/+ buffers/cache:        909       2082
Swap:            0          0          0


I might not be using the computer for video steaming, but I am using it at my workplace. and it has been up for 4 days now. (I power it down over the weekend when I'm not here.)
I have seen a few times where firefox will overcache information and cause issues, and you can resolve it be restarting firefox. I also use an addon to help manage the issue. "Free Memory" is the name of the addon, and I have it set to automatically clear data once every 15 minutes. It seems to help. I the system seems to stop responding to mouse clicks, in most cases you will still be able to access terminal by pressing [ctrl]+[alt]+[F1] and it will switch to another tty, you will need to login and then run

Code:

sudo killall firefox

and if you keep having the issue then a x restart may be required

Code:

sudo service lightdm restart

P.S. To be able to get back to your normal gui, you can press [ctrl]+[alt]+[F7]

I did install Z9-Lite, but it would lock up worse than Core. I started a movie playing on Core, and then opened up and closed different programs, and there was no noticeable slowdown in the machine until I had three other programs running and then opened Libre-Office. While L-O was actually loading you could tell that the machine was working kind of hard, but no where near lock up hard. I am beginning to think that the NetFlix Desktop app for Ubuntu is buggy, or something. I think It's in the app whatever it is. The only time I have problems is when using the desktop app. Of course it could be because it's using FireFox as a base. I used to use FireFox, it was my favorite browser for years, I wouldn't touch another browser. But, it got to the point that FireFox would over cache to much, and I would have to use the System Monitor/Task Manager depending on the OS, to kill it, then restart it because it wouldn't respond at all, and half the time it would take either a ctrl-alt-del, to stop and restart window manager, or just hard reboot. I thought it was my machine at the time, then I started using Chrome and never had the problem, so I found the problem by process of elimination. I am going to try and see if I can Chrome OS (beta) installed and see if it works, as it plays NetFlix nativately. My other option is to by a copy of windows 7, and M$ won't get anymore of my money at all.