HP Envy start up issues and fan speed

[jtmusic]

I have a Envy phoenix 810....when power is turned on you can hear fan start but no video and after a couple of seconds fan speed increases very high...only way to shut down is holding power button...computer always repeats and will not start...no signal to video screen

[itsmyname]

@jtmusic -- when you power-on your computer, it first launches the POST (Power On Self Test).

Part of the POST is to speed-up the fan to 100% speed (and noise). 

If the temperature of the motherboard and the processor are "normal", POST will tell the fan to slow down, and get quiet. 

But, in your case, due to some hardware problem (before the video is initialized), that does not happen.

Do you get any "beep" sounds, or blinking lamps?

Are the beeps/blinks showing a repeated pattern, e.g., 3-long-2-short, to indicate the specific nature of the problem?

[jtmusic]

No sounds or lights that indicate any issues....when I did remove the RAM memory and restart it did beep so I do understand what you are thinking. At this point I am thinking the mother board is probably bad. ?

[itsmyname]

@jtmusic -- before "discarding" the motherboard, I would do a few things:

1. temporarily connect a different power-supply to the motherboard (and the video-card, if necessary), but not to any CD/DVD/HDD/SSD.
2. remove all the sticks of RAM. Put one stick back it -- to "re-seat" it.
3. if your computer has an add-in video-card, and integrated video, remove the add-in card, to force the computer to use the integrated video (connect the video-cable to the video-socket).
4. if your computer does not have an add-in video-card, to force the motherboard to bypass the integrated video, add-in a "known good" video-card.

After the above, restart, to see what happens.