Computer locking up

My computer seems to be randomly freezing, sometimes when it is in use, other times not.. (Ex, I'll be playing a game / typing something, and it will completely freeze, other times I'll be out, come back and see the computer frozen with the clock several hours old...)

I recently installed a new power supply & video card, which I am pretty much positive that one of them are the problem, as I did not have this problem before they were put in.

I installed a "Coolmax" 450W power supply along with the Ati Radeon XT1600 512 MB video card..

My computer motherboard supports 4x AGP, and the Video card I bought is 4x/8x. The old video card I had in their worked fine (4x), but do I need to configure an option to set the AGP slot to run at 4x instead of 8x? Are there drivers that I can update on my computer? Or is it simply that my computer is too old to handle this video card..

I'm not totally sure.. Here's the thing; when I take out the power supply and put in my old video card which only requires the stock PS, then the computer works fine. However, a few months earlier I had a video card which required the 450W power supply, and my computer was doing this same thing.. I thought it was the video card so I took it back, not thinking that it could be the power supply. (Can it?) Now I have the new video card, same power supply, and the computer is suffering identical problems. I'm guessing either my computer will not support newer video cards that can run at 8x AGP, OR, the power supply is bad.

Is there any way I can test these?

A few more things I want to add. I ran memtest 86+, which the memory passed the test. I have also been monitoring my computer's internal temperatures using SpeedFan, and the max temp is anywere from 55 - 60C

Any help is greatly appreciated

8X/4X boards support both. Did you uninstall the old drivers and then install the new for your graphics card?

The thing about the clock leads me to suspect the PSU.

Also can you clarify my confusion here: " when I take out the power supply and put in my old video card which only requires the stock PS, then the computer works fine. However, a few months earlier I had a video card which required the 450W power supply, and my computer was doing this same thing."

You took out the new PSU and new card and all was well? i.e. Old PSU/ old card.

What about the new PSU with the old card?

What is the make and model of the motherboard?

If you do not know try this scan and post back the info under Main Circuit Board

http://www.belarc.com/free_download.html

First, I'd like to say thanks for the fast response

And sorry about that.. To clarify, yes, when I took out the new PSU / card and put in the old PSU / old card, it worked fine. I haven't tried with the new PSU / old card, I should try that.

My computer is a few years old, a compaq presario 6410nx. The chipset is a Via KM266 8235. I'm not completely sure on the manufacturer.. Would running that program tell me the manufacturer, or is the chipset all you needed to know.

Thank you for your help.

Edit: I was looking at my computer specs, and the APG 4X slot says it is 1.5V. If the power supply is something different, could that be causing the problem?

Computer here:

http://h10025.www1.hp.com/ewfrf/wc/p...&lang=en&cc=us

But they do not specify the motherboard.

I would like to see what Belarc lists if you will.

Board: KM266-8235
Serial Number: 132858-30405408
Bus Clock: 133 megahertz
BIOS: Phoenix Technologies, LTD AM37308 12/16/2002

That voltage is standard for an AGP 4X/8X card.

I would try your old card with the new PSU just to see if any issues persist.

I have been running my computer with my old video card and new PSU, and it hasn't frozen yet.

But I can't be all too sure, because I have only been using it for about 5 hours, and sometimes the new video card would go for longer periods than that without locking up.

Does that mean my computer is incompatible with newer video cards, since two have caused the same problems?

If my computer does crash with the New PSU / old card, does that mean the PSU is bad, or once again my computer is simply incompatible?

I think I'm going to look into building a new computer..

My computer is still yet to freeze with the old video card / new PSU, nearly 12 hours.. It would have definetly frozen with the new card by now..

So, this means what? I guess my PSU is ok, but have I had really bad luck with video cards and got two that do not work with my computer, or is my computer just too old to support them?

That is a very high end graphics card to be running on a 4X board but technically it should work although at the limited 4X speed.

My best guess is that that card is just too much for that motherboard.

Alright.. My computer is pretty old anyway, was bound to get a new one sooner or later.

Thanks a bunch, you've been very helpful