Vizio has gone a bit round the bend

I've had my Vizio 42" tv for over 7 or 8 years, recently the screen has been behaving a bit odd. First time it happened was about a year ago, it made a pop sound and the picture went away. Turning it off and back on produced a mostly black screen with a grey bar at the top, and what looked to be the bottom of the broadcast barely peeking out at the edge of the top of the screen . Went online tried a few fixes, changing outlets, draining it of all power while unplugged, with little results. So I just turned it off and let it rest, then turned it on again a few hours later, the picture was back just fine. A few months ago it happened again in the middle of the night, tried all the same things again, left it and a day later the problem persists. Two days later no luck, so unplugged it again and left it.

Was about to take it to the curb for trash but on a whim plugged it back in. Works fine now! Still had a flickering bar at the top when it was first turned on but it went away after a few minutes. Does anyone know what might be going out on it that could cause this and is it an easy or cheap fix?