My dad wants to use an old flatscreen as a larger monitor for his laptop so he can see better. I connected it with an HDMI cable, and the desktop shows up, but the display looks green, noisy, and constantly jumping (it would really help if I could post photos, but oh well). The monitor is pretty old (bought it in 2009), but the laptop is new as of last year, so maybe it’s just a hardware incompatibility? Can anyone think of a way to remedy this or another way to connect the two? I am moderately tech savvy, but have had virtually no AV experience. TIA!

Laptop: Lenovo Yoga 7 16IAP7, running Windows 11

TV: Vizio HDTV VX240M