Brand new Desktop Pavilion. Everything turns on but I get no signal display on the monitor. Tried different cables no help. Hooked up monitor to different computer and it worked. Hooked up different monitor to computer and same no signal. Tried all the troubleshooting. What next?
Not much you can do to troubleshoot when there is no display.
You paid for free HP Tech Support as part of the warranty coverage, so you might as well make use of it.
While this PC is still under warranty, you should contact HP Customer Support directly to have them put you in touch with HP Technical Support to see what they can do about troubleshooting and repairing your machine remotely.
I did this recently and the HP Tech was able to remotely access my PC from the Internet and do the needed repairs.