Well I just got off the phone with HP as well as one of their distributors in trying to find the Power Supply I needed but to no avail! I was hoping someone could point me in the right direction?

HP Pavilion 7955 Desktop

The factory power supply model is BST ATX 1956DA. Its an older model psu with a 20 pin connection.

Any help would be AWESOME thanks!I wish i were in a position to point you to a specific interchangeable PSU for your computer model. I am including an HP document that is designed to assist in how to go about determining a suitable replacement. I am also including a reference to a specific alternative that i would suggest you investigate to it's suitability and availability.http://h10025.www1.hp.com/ewfrf/wc/document?docname=bph07139&cc=us&dlc=en&lc=en&product=62740
http://www.outletpc.com/da7661.html
There may be others that purport to be interchangeable. I urge you to use the search parameter "interchangeable alternative psu for an HP Pavilion 7955 Desktop" and see what comes up. good luck,truenorthDid you try Ebay? Any ATX 20 pin PSU will work...doesn't have to come from HP...
Some 24 pin PSU's will work as well...the extra 4 pins are not used.patio, Hopefully the range of options for the O/P is as extensive as you suggest. However my own limited knowledge in this area (specifically HP PSU's) is it becomes less of a concern as to abilities to provide the proper voltages and connections but rather the limitations incorporated by HP as to physical space CONFORMATIONS that HP seems to go to some lengths to create that insist on THEIR own HARDWARE. Hope that is NOT the case here. truenorth http://www.cputopia.com/psu-replacement-300w-hp-compaq-7955.html?gclid=CLaM6dis2K0CFY-R7QodPSW02wThe worst I ever had to do was with an old Pentium 4 Dell tower, they didn't have the proper opening in the back of the case for the power CORD to connect so I had to drill my own, but even with their proprietary design and tight fit, the power supply was still the same size and installed the same as any other one i've seen. I've never seen a power supply that was a strange size or a specific voltage only that any other manufacturer's PSU did not fit and work.Dell had some: http://www.informit.com/articles/article.aspx?p=339053