Samsung goes black -no picture, only sound

i have a samsung PN42B450B1DXZA plasma television, 42" bought about 3 years ago.

i dont know if this is a cable issue or if this is a tv issue. i called the cable company and they spent about two hours doing tests, replacing the cable box, new wires, checking the pole outside, etc. as soon as they left tv went black while watch regular television.

when i watch my television, it goes black randomly. sometimes its after two minutes of watching tv, sometimes its after hours of watching tv. in order to get the picture back i have to shut down television, wait a few seconds then turn tv back on. sometime picture immediately goes black again, sometimes it will be hours before it goes out again.

i have tried using an HDMI cable, but no luck. perhaps i can try a better more expensive HDMI cable.

can anyone offer suggestions on what the problem might be.

**just as a note, when the television goes black, i cant access the television's menu.

also, should it matter whether the cable signal is 1080i or 720p? i think my tv is 720p.

while im at it, maybe someone can recommend an HDMI cable that i can get.

maybe this?
http://www.newegg.com/Product/Produc...82E16812189053

i know nothing about cables

ive seen monoprice site before but bypassed it.
i guess if they're a sponsor im going to give them a shot and order my wires from there today.

another question, although random.

should it matter if my cable box is giving signal of 1080i or 720p? that shouldnt cause me to have problems can it?

ive had this problem at different times and the cable tech has come at two different times. most recently the cable techs came and swapped cable boxes, wires, etc and checked connections and he said he ran tests and found no issues. when he left the tv went black again. this was recently.

i just ordered new hdmi cable, so ill try running the apple tv box and stream from the internet...and other things as suggested.

i ordered cables from monoprice.

for the cable box, i switched the video/audio cables with the new ones from monoprice. after 1 hour, screen goes black.

i also have an hdmi cable i ordered for the Apple TV. so i switched to the Apple TV with the new HDMI cable and screen goes black within 30 minutes.

surprisingly though, i have had a dvd play for 2 hours and it does not go black. its using the old video wires (3 wires instead of 5). i dont know how else to test the tv with the dvd player, its an old dvd player but a whole dvd plays without the picture going black.

im about to switch cable/internet to FIOS just to see if this will still give me problems. both the cable and internet are through Comcast. not sure if this is the issue, but FIOS tv has a sale going on, i want to try something new.

but at this point, im clueless on what the problem could be. maybe its just the darn television. stupid samsung