My computer is having issues connecting to monitor

[Animund]

Alright, so I just bought this desktop 4 days ago off Amazon (so it is brand new, from what I know) and the first 2 days it booted up perfectly fine, no issues or anything. Nothing has been changed between then and now (including programs, stuff I have on the computer, etc.). I use a small RCA TV for my monitor and they are connected via an HDMI. What seems to be happening is when I go to turn it on for the day, the lights will turn on, but then the screen will display "Unsupport" (as though there is an issue with the HDMI cable or monitor). It will stay like this for roughly 3 to 5 seconds, then the fan in the desktop will whir, the screen will turn black and then it will display the same message again. It does this once or twice until it actually boots up Windows and I'm able to use it. (*Note*: When I restart the computer it will only do this once then boot up normally.) When I first experienced the issue, I figured the HDMI cable was bad or something, so I swapped it out for a brand new HDMI cable, that did nothing. I also used another monitor I own and it does the same issue. I'm not sure on what to know is going on and some assistance would be greatly appreciated!

[Echo_Lake]

 @Animund

Thank you for posting on the HP Support Community.

• Did this happen after a recent window or software update?
• Have you made any hardware/software changes?
• What is the product number of your device? Use this link to find it: http://support.hp.com/us-en/document/c03754824

While you respond to that, let's try these steps: (do not skip any troubleshooting steps even if you feel steps are repeating)

• Note Before you begin: Turn off the computer.
• And disconnect all connected devices from the computer except the mouse and keyboard. This includes removing thumb drives and camera-type memory cards.

Step 1: Checking the power

Step 2: Displaying a built-in on-screen message

Step 3: Fixing a bad video connection

Step 4: Testing the video connection

Step 4: Connecting the monitor to a different computer

• Use the steps in this document: https://support.hp.com/us-en/product/hp-value-23-inch-displays/7274744/model/10402854/document/c0129... to resolve this issue or to determine if the monitor is defective.

Hope this helps! Keep me posted for further assistance.
Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.