Dell XPS420 - Turning off / Locking up randomly

[oldskooladdict]

A colleague has a Dell XPS 420 which is exhibiting very odd behaviour, frequently (2-4 times a day), here's what happens...

The PC is working fine, and being used normally – nothing overly intensive, Outlook, Photoshop, Internet Explorer – so nothing major on a quad core machine with 4GB of ram. Then, with no warning the monitor turns off and the power light goes from blue to orange, and entering power save mode is displayed on the screen. On the base unit the blue light is still lit on the front and is solid (not blinking) or anything. The keyboard still has lights for caps/num lock – however these don’t respond when pressed.

The only way to recover the PC is a hard reset, this is often required multiple times before the PC is stable again, for a few hours.

This happens when my colleague is actually using the PC, not when it's idle. It happened to me on Friday when I tried open the event viewer - just clicking on event viewer made the screen go into powersave and the machine lockup!.

So far I have tried:

* Looking in the event viewer for events prior to the machine freezing which would explain it. Nothing out of the ordinary, all information messages and nothing you wouldn't see at other times.

* Updated the graphics drivers from NVida, it now has 19-August-09 drivers or there abouts.

* A new DVI cable (as we have some spare ones) and it was easy to eliminate.

* Memtest 86 - This ran for about 5 seconds then tried to boot the machine, very odd. So, I removed 1 stick of RAM from 1 slot and tried the test again, this ran for around half hour then I stopped it as nothing odd had happend. I tried it again with the same stick of RAM and it failed in the same way, so I thought I had sorted it.

Unfortunately the same thing has happened again this morning so my memory removal didn't solve it.

I've had PCs freeze in the past but never the monitor die straight away, this seems most odd.

Does anyone have any tips what I could troubleshoot next to try and solve the problem? -The machine's one of our best (was!) and used frequently, and it's out of warranty.

[Phage]

Heat ? If it's old machine, how much dust and cruft has built up around the heat sinks ?

[oldskooladdict]

Only about a year old and quite a big tower so I highly doubt heat is an issue. I popped it open on Friday for the RAM tests and it looked very clean and tidy in there!

[Phage]

I'd run the memtest and let bit finish. Things did improve when you changed RAM.
What did the event logs say ?

[oldskooladdict]

The RAM stick I thought was faulty has been removed now so it's running on 3GB rather than 4GB. I could leave the memtest running overnight I guess and see if that chucks anything up. Still think the monitor thing should be key to all of this somewhere!

[Phage]

Your OP states that the monitor is still functional though.
"and entering power save mode is displayed on the screen"
Why would you think it's the monitor ? Is there some other symptom ?

[oldskooladdict]

What I'm saying is that when a PC usually locks up (in my experience) the screen stays on and the PC just freezes or blue screens etc. It says this entering power save thing then the light goes orange.

I may not be explaining myself well but I'm sure this is some kinda clue!

[Phage]

I agree. But I think the clue is in the message displayed. As the monitor is obviously still functional, as is the GPU.
For some reason the machine is going into sleep. I cannot imagine why it would do this other than an error in what it thinks it is going on. memory failure is my first thought, but a bad PSU may also have odd effects. Does anyone else have an idea ?

[oldskooladdict]

I used something to monitor the temperature, the graphics was running at around 110, even topping out at 116 (that's degrees c!). I popped it open and sure enough it was hot, a colleague who builds PCs looked at it and the fan wasn't spinning basically. Taking it out it looked to be moving freely so not sure what was up with it. We put in a new graphics card and it's running at 55 degrees now.

Hopefully this sorts it, time will tell I guess.

[Phage]

Sounds like you found that it was indeed a heat issue !
Glad to hear that it worked out.