HELP!! MY LCD TV has these wierd mixed up scrabbles of colors, the picture gets all scrambbled!?

HELP. MY Westinghouse LCD tv is okay when I initially turn it on then after its been on for about 20 minutes the picture gets fuzzy then all these colors start scrambling around the skin and the picture cannot be seen at all. Is there something I can do without the hle of taking it to the store to get looked at?