New Power Supply

I'm interested in upgrading my graphics card from a GeForce 6800 to something a little more powerful for games. For the new card, I need to get a new power supply, too. My computer is a HP Pavilion, d4100y, and I've heard that HP puts specially-sized power supplies into their computers in order for them to fit.

My question is, will I be able to upgrade my power supply to something bigger, keeping the HP tower, and how can I tell a new power supply will even fit before ordering it? Any suggestions welcome.

FYI, this is the one I was looking at buying.

 

I think you should be able to upgrade without a problem. I would however measure the dimensions of your power supply you have and compare it to the one your looking at buying.

 

when i replaced the PSU in my sony vaio, i gambled and...it didnt fit. the new PSU was MUCH bigger than the sony one. I ended up buiying a new case to stick everything in but i doubt you'd want to do that...Like squeaner said, measure yours and compare it to a full sized psu