No signal when laptop wakes

[kachampong]

when I wake my laptop the connected 42 inch tv screen shows "No Signal"

 

[kachampong]

sorry to sound so rude and not intro myself properly, new to this. ive been trying to find a solution to this for ages as the laptop is hooked up as a htpc but when waking, the screen shows no signal. i open the lid and close again, everything is fine. any advice greatly appreciated. thx