My Pc Not Turn On

traktori Posts 74 Registration date Thursday April 16, 2009 Status Member Last seen January 26, 2015 - Nov 19, 2012 at 01:45 PM
Hello,i have a pc dell a8300

1) sometimes my pc doesnt start there lights on in motherboard i press power button and nothing
2) sometimes my pc turn on and it freeze and after in monitor says no signal
3) sometimes my pc until working playing games it freezes and i need to restart it because it all freeze mouse keyboard and everything
I thought there was a graphic card problem and i changed it and seen in 24pin cable connector and there were burn smell and again it works.
sorry for my bad english PLS HELP ME