My PC had the blue screen of death "physical dump" menu this morning and then shut down. When I powered it back up it has no display, keyboard, or mouse activity. Has anyone else seen this before?

Obviously something really bad has happened. Unfortunately you have not provided enough information to help you.

When you get a blue screen, if you can write down the hex codes looks like 0x8000005C (0x60000001 0x00000000 ....
knowing this part of the message can lead to the solution. Unfortunately, it's not always possible to write the information down before the machine reboots.

Ok. Now that you cannot boot, we need to determine what exactly is going on with your computer. Do you hear beeping? Do you see anything at all on the monitor? are the fans running?

Here is a little more information. The machine has power, the fans are running, and the hard drive is spinning. When the computer is first turned on the red led on the mouse flashes once, but then the light stays off. There is no keyboard activity; the Num Lock or Caps Lock does not come on. The monitor briefly comes on and states "no display" and then goes to sleep mode.

Does this help or is more information needed? Thanks for your help!

Have you recently made any hardware changes? Sounds like a memory problem to me. Definitely hardware. Try unplugging everything but the power and video cable just to make sure it's not a peripheral.

Some new computers, even desktops use a small portion of the main memory for video and a video or memory problem can cause this error.

Most likely you will need to take your machine in to someone and have it properly diagnosed.

Remove all RAM and and Replace one at a time if you have more than one stick. What OS are you running?