PLEASE HELP!

I have a tv who's vertical circuit seems to have gone out. Turned it on this morning, first a ~1" wide horizontal stripe appeared, then moments later it changed to a vertical strip from near halfway down the screen to the bottom. Sound is perfect. I'd like suggestions on how to repair, and I am no TV tech - even would like to know how to open the back of the TV.

Can't afford a repairman, don't want to lose this TV, Can you help/guide me?

Either way, thank you!

pu