Everything is fixable, but it is a 17 year old set, with old technology. In these days of Internet connectible, Smart televisions with 4K picture quality, you would notice a big difference. I would say you have had your moneys worth out of it. Its up to you, service centre, or a new one.
Panasonic TH-PX77U review - CNET.com
www.cnet.com > reviews > panasonic-viera-th-50px77u...
Apr 12, 2007 - Panasonic's internal menu system is intuitive enough, although we disliked the ease with which you can inadvertently erase your picture settings. With a native resolution of 1,366x768, the Panasonic TH-50PX77U matches the resolution of just about every available 50-inch plasma today.