HP printer "Scan" button borgets its function on restart

Hello all,

I'm trying to setup a HP Photosmart C4280 All-in-One with an iMac (about a year old) with Leopard. Everything seems to work fine, except for the "Scan" button on the printer. When you press it, it thinks and then returns "USB Not Connected". (The scanner works fine when driving it with the software, just not the physical "scan" button.)

Now, I did some research and found that it could be outdated drivers/software. I went to HP's site and downloaded the most recent goods and installed them.

Success? Well...partially.

Upon installing the software, the button works when pressed. But, if the computer is rebooted, it seems to forget how to work and returns to "USB Not Connected" mode when trying to scan. (If I re-install the software, it will work again -- until rebooting, that is.)

Now, the thing I need some assistance with is this -- what could be causing this seemingly forgetfulness after restart? Are there any tips on how to solve this?

Thank you all very much in advance!