No display signal and pc wont power off via front button.

Hello,
So i recently built a new pc. Everything worked alright for the first month. I recently relocated and moved the pc in the back seat of my truck. After hooking it back up in the new house everythings worked fine. About two weeks ago it started ditching signal to my tv. I would power it down via the front power button on the tower. Reboot it and everything was fine again. That happenend 2 or 3 times. Then it stopped. Today it was on running normal then i got the no signal screen on my tv for the pc input. Not using hdmi and have the right adaptors for my tv inout from the pc. I went to power down via the power button on the front of the tower. Held it in for 30 sec and it just stayed on. So i resorted to manually powering it down via the switch on the power supply. Restarted it. No signal and couldnt power it down via the front tower button. Im oretty new to computers and would like to figure this out sooner than later. Any suggestions would be great. Tbanks in advance.