I drive a '99 civic DX and recently I have been having some weird problems. Sometimes in the middle of driving the car, out of nowhere the car will just shut off. The engine doesn't hesitate at all and the only way I know immediately that it does it is because the power door locks unlock and I can't accelerate. Also sometimes when I go to turn the car on all of the lights in my cluster blink real fast and I hear a clicking noise coming from the ecu area. Not to stop there buy my a/c pretty much doesn't come on most of the time and my passenger side power window (after market) doesn't work most of the time. If anybody has any ideas whatsoever as to what could be causing these problems please help me out. It's getting kind of dangerous to drive through an intersection and have your car die half way through the light.
Also not sure if this has anything to do with it or not but the car used to be an automatic and was converted to a manual.

Problems:
#1 Car shuts off without warning (three or four times in last three months)
#2 A/C works about 10% of the time
#3 Passenger side window won't work but about 10% of the time
#4 Cluster lights blink and ecu makes clicking noises sometimes

Please help.