While you are pushing your luck with the PSU the TDP seems to be not enough for me to write it's the problem.
Since you never get to the windows loading screen it could be one of those rare BIOS issues. Be sure to unplug all USB things and try again (no USB!! not even the keyboard and mouse.) After that I fear it's the usual "this doesn't work in that issue." Check on the hp.com site for your model and hope they updated the BIOS.
I bought a new video card, PNY GeForce 730 2GB from Best Buy to replace my GeForce 520 1GB.
Upon booting up, the computer freezes at the blue HP "press ESC for setup" screen and beeps once than twice.
I've read that the beeps signify a video card issue not being recognized or not seated properly. Card is inserted all the way and the cooling fan runs. Driver was installed and is up to date.
The only thing I can think of is the PCI connection. My motherboard has the long x16 length and that was the configuration of the old card. This new one is very short. It is more than half the length and does not fill all the slots.
Do I need a card that has the full PCI x16?
HP Pavilion slimline
12 GB Ram
Intel i3 2120
GeForce 520 video card
Power Supply max rating 220W