Sound ok no picture hp invent comes on then the screen goes gray

Sounds like defective capacitors on the power board

I suspect you have a poor contact on the video processor board or the upscaler itself on the screen.
Check all ribbon connectors and look for any components that have got very hot, there may be a dry solder joint beneath them.
Hope this helps.

If screen is gray glowing, the T-CON is bad or it is not getting the 12vdc from the logic board. You may have problem with logic board but do some voltage checking first.
If you are going to DIY and have proper tools and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague
Parts: www.shopjimmy.com

try to run the hdd test in the bios page and see what it says. if it says no ide device found, try to reseat the hdd.

Contact HP at 1-800-HP-INVENT
-=/ Daft Tech /=-

if you have external jet card remove it and restart

check the scart cable/adaptor

I had the same problem which showed the exact screen you're describing and was able to sort it by downloading the ROM update from the HP site - they show it only available for US but works fine on UK machines as well. It takes a short while to install but has restored mine back to normal again. (only problem was incompatability with windows vista - works fine with XP)

What are you using to connect to the monitor? Have you tried replacing the cable, sometimes cheaper HDMI cables can cause this issue

I’m happy to help further over the phone at https://www.6ya.com/expert/joshua_ac64e182ed26f66d