I got a replacement from click here they are not cheap. That one also went so I eventually modified the HP case very slightly and am now using a 'standard' 300w. The HP ones are underpowered, my first one was 185, next 200.
Get the full details from your present ones label. If I remember correctly there is a search facility on Bits and PC's website.
Ask for more help if need. I should have said that my old machine is a Pavilion 8685.
I am not sure which HP model the computer is as the computer is my brothers that he blew the power supply on. We have tested it with one of my old power supplies and it works fine, but of course it is to big to fit into the case.
How exactly did you mod the case to fit in a normal PSU.
The standard psu fits with a mm or 2 to spare without touching the sound card, but I had to bend the back panel below the space where the power socket of the psu fits to give space for the psu switch. I used pliers to do this very gently, and the screws then go in as normal to hold the psu in place.. It is a very close fit, and probably depends on the type of HP. I think the cases and the layouts vary between models.
I checked the Bits&PCs website and it seems it would cost almost £100 to replace the psu now.
Hope that is some help. If I had not got the psu to fit I was going to re-case the whole thing.
I originally decided to re-case, and had a discussion with my friendly techie at PCW. I bought a case which included psu from them. Howerver having worked out thata re-case should be possible I thought I would check out the psu. Took it out of the new case fitted it into the HP and adjusted as described. Case and psu 300w cost £37. As a result I ended up with a shiny new case which my wife took a fancy to and I have now built her a new pc for about £200 but I had to buy a new psu for the new case!!! and a new os. Hope you sort something out.
A thought why not go to PCW and ask if you can measure their psus I think they do one for about £25. You can then decide what to do.