Computer boots to white flashing screen - unable to do anything after log in

[Bryce4]

My computer begin blinking a white screen after being shut down by a power outage.  The computer boots to the log in screen allows me to log in then briefly shows our desktop picture but then begins blinking a white screen and nothing else can be done at that point.  

When trying to troublshoot it I have run into the sihost exe - system warning   unknown hard error.  Searched fixes for that issue using command prompt but both fixes suggested failed.  Also tried doing system resets without erasing all of our files and all reboots fail.

[WAWood]

@Bryce4 

You mention a power outage -- so did you lose complete power in the room where the PC was being used?

The outage is not the issue; the issue is that when power comes back on, you can have a power Surge -- and without the PC being connected through a surge protector, that can do major damage to a desktop PC.

To determine the cause with hardware failures, you have to be able run diagnostics. We have no way of accessing your PC from here, so we can not do that for you. You have to do it yourself.

You do this by pressing the Esc key repeatedly when rebooting and then, when the HP Startup Menu appears, selecting Diagnostics (usually F2) and letting it run.

If it is NOT possible to run diagnostics, or if that does not work, then there is NOTHING more you can do by yourself -- and there is NOTHING we can do because we have no way of accessing your PC from here to run diagnostics or repair hardware.

You will need to have the PC physically examined in a service facility by folks that can run their own diagnostics to determine what is wrong with it.

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If your PC is still under the original one-year HP warranty, or if you have purchased an extended warranty from HP and this is still valid, then having HP do this is an inexpensive option for you. In that case, you should contact HP Customer Support to see about having it repaired or replaced under warranty.

To contact HP Support see the following link to create yourself a case number, then call and it may help speed up the call process:

Step 1. Here is the link: https://support.hp.com/us-en/contact-hp
Step 2. Enter Product number or select to auto detect
Step 3. Scroll down to "Still need help? Complete the form to select your contact options"
Step 4. Scroll down and click on: HP contact options - click on Get phone number

Case number and phone number appear.
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If your PC is no longer under warranty, then it will cost you up front to have HP examine your PC. If you want to do that, you will have to contact an HP Repair or Service Center to see if they can examine the PC to determine the cause(s) of the problems, if it can be repaired, and an estimate of the repair costs.

Since you live in the U.S., here is a link to the HP Service Repair Centers:
https://www.service-center-locator.com/hp-hewlett-packard/hp-hewlett-packard-service-center.htm

If that link does not provide the results you want then use the main HP link:
https://support.hp.com/us-en/contact-hp?openCLC=true

Good Luck