My PC doesn't give a start-up beep.
It has XP-PRO and it was very good.
I built it myself and I am proud of the tuff little PC.
But, everything gets old, I understand that.
I don't see any blown capacitors, so WHAT's UP !!!
NO BEEP !!!
most times it the power supply that loses a leg on old system. see if a friend has a spare or have yours tested. a lot of micro center have walk in tech support that can plug a cheap go/no go tester on your ps.