Display weird. Boot freezes

[Ima poster]

Hi. Last night the display on my mid2011 21.5 imac froze with a snowy picture. Today I have vertical bars with snow interleaved with decent screen. Also the boot freezes about 1 cm before the bar hits the end. Any ideas on what to try? Can't see any other similar posts but I'm trying do do this from my phone :-(. Would add screen picture I took on my phone but can't figure that out eithe. Thanks for any ideas.

 

[Samuelsan2001]

Sounds like the gpu has died, at that age a new logic board is not worth the investment you are probably looking at a new computer.