I have seen this in very few systems that I have worked on. They have a mini power supply in them. This sounds like your system since it's only a 150 watt like you stated. You will not find a power supply that has a higher wattage output and will fit corrrectly in your system. Trust me, I know. If you do, I'll send you $5.00 through PayPal.
You now will need to buy a new case and put all your current stuff in there. Once again, I think it would be better to just build a new system and then keep this old one as a net backup machine.
Please keep us updated, I'm following this thread.
