If I understand your post well, you connect your PC's displayport output to your TV's hdmi input via an adapter, and it doesn't work.

- What TV exactly?
- What adapter exactly?
- What graphic card in the PC? https://support.hp.com/au-en/document/c03846648#AbT2 shows 4 different ones are possible (apart from the integrated graphics). Latest driver for that card installed?
- What resolution and what refresh rate is output by the PC? What resolutions and refresh rates are supported by the input in the TV?
- If you connect a 4K monitor directly via displayport (without adapter) does that work with the same PC settings?
- Are there any resolutions/refresh rates that work with this adapter?
- Does the hdmi out (PC) to hdmi in (TV) work?