i have a dell dell optiplex gx50 tower and i am having an issue with the signal to the monitor. When i connect the tower the monitor it says no signal, also when i turn on the tower it beeps three times. I am not sure if the beeps is at all related to my signal problem. i have no knowledge of this tower, i was given the tower awhile back, but the guy said it was refurbished. if anyone can help i would greatly appreciate it. if more info need please tell me.