Desktop freezes, then shuts down.

[jat470]

A few weeks ago my desktop began freezing suddenly, then shutting down. Depending on how much time elapses between attempts, the computer usually boots up normally (sometimes freezing at the welcome screen, or on the options screen after I hit F12), but it always ends the same way with the computer eventually shutting down. I replaced the graphics card and when that didn't resolve the issue, I replaced the hard drive and reinstalled the OS (Windows 7 Home Premium). Also, the amount of time between when I boot up and when it crashes is also variable, which is how I was able to reinstall Windows, only to have it freeze while attempting to install the drivers.

Now I'm not sure what I'm dealing with. Could it be a memory issue or CPU? I'm assuming it's some hardware issue, but I'd like to narrow things down before I go buy another component. Any ideas?

[Geek-9pm]

Here are some general comments about how to troubleshoot desktop PC.
Whenever you do it yourself, you don't have ready access to custom software provided by a major manufacturer. The best you can do is look for diagnostic software from the maker of the motherboard. You'd be interested in two specific things. You need some kind of test for your memory system and renewed some kind of test for your hard drive. You may want to try the memory test first.
Now the hard drives. It is said that her drive failures might be nearly 80% of the failures in older computers. But that would mean that 20% of the time it has nothing to do with our drive. Well, if you've already done the memory test that pretty much is a fair test of the hardware other than the hard drive system.
The major hard drive manufacturers usually offer some kind of diet the tool for their specific hardware.

In my opinion, it would be a good idea to purchase a new hard disk drive and keep it on hand for occasions when you suspect there might be something wrong with your hard drive. You can use a modest size hard drive to get the system up and running. For example, hundred and 60 GB hard drive is more than enough for an installation of Windows 10 and a couple of your favorite games and other programs. You could try doing a minimal installation of Windows 10 and a couple of your favorite programs on a new 160 GB hard drive. Letting the hard drive have lots of free space is actually a good trick. This produces an effect that to causes a parent speed up in the system because the hard drive has all the data just in a small area. Have a name for that but I forgot that the call.. Anyhow the idea is that your half a small amount of programs and data on a fairly large drive. The 160 GB hard drive is viewed using only on stalled Windows 10 and a couple of programs.
Of course that takes some time, but time will spent. You will now have a spare hard drive that can be used to do a quick test of your system and see how the performances.
By the way, the solid-state drive does really does increase performance. However, even without the solid-state drive, your system should be reasonably good performing if you're system is working properly.
The problem with hard drives is sometimes you get bad sectors and the system just keeps retrying the same sector over and over again about reporting to the user that there's something wrong. This is just a design decision that somebody made in the business. And by the way, I used to work in hard drive research. So I think I know a little bit about how hard drives for at about how manufacturers try to cover up the performance issues.
That is much as I can do for you now.

End of dictation.   

EDIT: Somebody might tell you to format your old hard drive and start over. The is rather extreme and you lose all your material.  I recommend get a small cheap new drive and ding a windows instar to see if the performance is better.

[jat470]

Just to clarify some things:

The only thing on the hard drives (including the brand new drive with the newly installed OS) having nothing on them BUT the OS--all the important files are kept on external drives, complete with backups. So I'm not concerned with losing anything.

Also, the computer isn't staying on long enough to run the memory diagnostic.

[Geek-9pm]

Here are some more general observations about things that cause the desktop computer to shut down.
A common problem is the fan on top of the CPU might be dislodged and is not working well, or the heatsink and become dislodged and not making good contact with the CPU. You have to take a look at it see if that's the possibility. Of course, you should check the temperatures, but if the thing shuts down real quick you won't have time for that.
A similar problem can occur with the power supply. This is one I've seen for myself. The power supply fan quits working but you don't notice it right away until you look real close and see that the fan is turning very slowly but not really running at full speed. This causes the power supply to overheat and it shuts down because there is a thermal cut out thing inside the power supply. That does not necessarily mean the power supply is bad, it is doing what it's supposed to do because the temperature rise tripped the thermal cut off thing. The answer to that is to replace the power supply fan, not the power supply.
Another thing is a CD-ROM drive that is going bad and shuts down the entire system because it's growing too much current from the power supply. Again, it's not the fault of the power supply because the power supply has a occurrence limit thing that shuts down when the current is going over certain point. This can happen on a very old CD-ROM drive that is got to the end of its life. Rather than trying to repair the CD-ROM drive, you just disconnect it and see if that makes a difference in behavior. That does happen once in a while. A similar problem can come with a hard drive that starts and draw too much current for some reason. And, by the way, the solid-state drive can also go bad and cause the system to stall because his drawing access current. The solution is to disconnect the solid-state drive. Actually, you trying to disconnect anything that is not necessary for the system to boot. You get down to the point of where all you have is just the BIOS screen come up and tell you there is no hard drive present or it cannot boot find it.
In other words, there is something other than the motherboard that is drawing too much current and causes the system shutdown. In the case of the heatsink on the CPU, the CPU itself also has a thermal cut out and was shut itself down if the temperature rises too high.
Again, these are general observations. There always is the chance that you have a motherboard that's gone south. In a few cases a capacitor on the motherboard has gone bad and is causing the problem. That issue was fixed in the industry some time ago on it should not be a current problem with newer computers. The capacitors going in the modern computers are very high quality and hardly ever do we have a failing capacitor anymore. But it could happen. A failing capacitor usually shows itself by bulging or having some discoloration or something that indicates that it's not working right.
I hope these general observations of give you an idea of what to look for.

This is from dictation.