After spending a couple of days trying to install a 64 bit system, I discovered that some proprietary software I must use only works in 32 bit Ubuntu. So I have to downgrade.
But after 64-bit 12.10 Ubuntu was installed, the computer no longer detects the USB or the DVD drive in the boot manager! Arggh!!! It had been working when I had Windows, a broken 12.04, and no OS at all. I have a HP Pavilion dm1 laptop.
It's okay if my computer is completely wiped clean and all data lost. I just need a 32-bit install.