Windows 7 - Replacement PSU Question

I've had sporadic issues with freezes, and I figured out that it's because I have a 250w powersupply in a rig with a new video card + recording interface drawing power + new ram + cpu, etc...

The computer in question is HP Pavilion a6403w, I bought a Elite Power 460 Watt ATX Power Supply. Installed it, and was not able to get a steady stream of power (eg: sometimes it would turn all the way on with a few things plugged in, sometimes it wouldn't, there was never any consistency). I tried resetting the CMOS, removing the bios battery, not plugging in any extra peripherals, etc...and was never able to get any consistency.

Im thinking I just bought a dud and will be fine after returning it after work for an identical model PSU. I wanted to check with everyone and see if somehow I bought the wrong PSU type or there's anything extra that I should try that it might be my fault... anything; just getting one last check-in before i return the PSU

btw model information on the PSU + my rig are:
Micro Center - Cooler Master Elite Power 460 Watt ATX Power Supply RS460-PSARJ3-US
HP Pavilion a6403w Desktop PC - HP Customer Care (United States - English)

I wouldn't take it back just yet.

You now have 2 power supplies--old and new.

Do you get one set of problems with the old one and another, different set of problems with the new one?

Or do you get the same set of problems, with both the old and new power supplies?

Power supplies are not easy to troubleshoot without special tools, so it's best to have 2 on hand and compare the problems with each. It is possible both are bad, but I would NOT assume so.

So what you are saying is you used your old MB and added new CPU, memory, Video card and recording interface.

What I would do is
Unplug PWS from motherboard and replug in and see if it reboots
Remove recording interface and see if it boots
If not I would reseat memory and see if it boots
If not I would reseat video card and see if it reboots
If that doesn't work and your data is backed up I would try reinstalling Windows.

Let us know what happens

I'll reword, all of the additions were made long ago. I upgraded the videocard three weeks ago and has since been having sporadic freezing issues, I ruled out everything else, ran tests, reformatted, examined all hardware, and after a bit of lengthy research it came up being that the power supply being smaller than needed (the video card is stated as needing a minimum of 350 vs. the 250 that the stock PSU was), I purchased a new PSU, and ran into those issues listed in my first post.

With the old PSU the computer will boot, its just underpowered and will eventually lock up because of it.

What video card did you add?
I think the biggest issue is in the Quality of the supply chosen, Those elite power 460's are FSP OEM units that won't deliver their rated power> Cooler Master Elite Power 460 W Power Supply Review | Hardware Secrets
Corsair, Seasonic, XFX and a few others work best.

My current specs are:
Intel Core 2 Duo E8400
4gb of Ram
500gb SATA Hard Drive
Firewire Solo (powered via Firewire)
Raedeon HD6450

And a bevvy of USB devices that are taking power from it. All of which were powered by the 250w stock supply

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Micro Center - Corsair Builder Series 500 Watt ATX 12V Power Supply CMPSU-500CXV2

or

Micro Center - Enermax LEPA 500 Watt ATX Power Supply N500-SA

would be a good bet?

The last I heard, the Corsair Builder series had a pretty good reputation.

Not necessarily so with Enermax.

I'm going to go for a straight out swap with Microcenter and hope that the one I got was just a dud...

Actually the Lepa n500 and the Corsair CX series are both Channelwell PSH II units.

The Antec High Current Gamer (Seasonic OEM unit) would be my first preference> Micro Center - Antec High Current Gamer Series HCG-520 520W ATX Power Supply 23850

I ran back after work and exchanged the PSU for a new one... and same issue; it will turn on for probably a full second and everything will spin and itll die. no beeps.

I thought maybe somehow the mobo got fried in all of this, but I tried the old PSU and she boots up fine with no problem...

I cleared the CMOS + battery

what else can I try, I highly doubt I got two dead PSU's
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What I've tried
Resetting the CMOS
Removing the Battery
Resetting the ram
new cord
new outlet
triple checked connections internally
tried it without the hd or cd-rom attached
tried w/o peripherals

but... the old PSU works... and this is my second one from the store...

im pullin out my hair