Green lines at top

Hello,
1. This TV has always been slow to come on when either remote or button on it is used ... probably should have taken it back then, but since we seldom turn it off, figured it'd work.

2. TV has done well over the last 3 years, except in the last couple of months, there are 3 very tightly placed horizontal lines across the top (down about 3" from the very top of the tv), that stay on it constantly.

My husband used to work on the old tvs that had tubes (yea, a LONG time ago!), so if you will use real simple words for any ideas on how to resolve this, it will be appreciated! (BTW, husband says it's fixing to go out, start saving up to buy a new one ... it's ONLY 3 years old for cryin' out loud!)

Thanks,
jaws