I'm having a problem with booting a live image off of a USB Hard Drive. I used Startup Disk Creator to make an Ubuntu 11.10 live image on a partition on my external so that I can use it on various computers. I set it up with ~4GB of persistent data

So far I've tried it on two computers. One, a Dell, will boot to my external but it loads the select boot device very slowly. It hangs on a screen with an underscore for up to 5 minutes until it allows me to select which drive I want to boot from. After that, it works great.

However, on my primary computer it doesn't work at all. It's an Acer from 2009 and it won't even recognize the drive. I don't see it anywhere in BIOS or the select boot disk list. The light on the external will come on at boot just fine so I know it's powering it at this time.

Both computers worked perfectly with my 4GB flash drive that I had partitioned half and half (1st half FAT32 and second Ubuntu 11.10 live)