I have an HP computer with a 19 inch monitor. Yesterday I was on it and all worked fine but this morning I turned it on the tower came on but when I turned the monitor on, the light was green and in less than 30 seconds I heard a click and the light turns yellow. The monitor never lit up, it was like it went to sleep before it came on. Checked connections and tried turning it on and off several times. Monitor gone bad or what? Thanks.

If you have access to another monitor, hook that up
-If another monitor works, it is your monitor seen it's last day unless you take it in to get repaired

If this is the case, it would probably be price comparable to purchase a new monitor

Sounds like a bad capacitor in monitor

But try another monitor to confirm