USB install not moving past bootloader

[wolrahnaes]

I am trying to move back to Ubuntu on my home file server from Windows Home Server. This machine has never had an optical drive, nor do I even have an operational one in the house (they've all failed over the years and I use optical so rarely I haven't seen a reason to care) so I'm trying to install off of USB.

I am attempting to install Ubuntu Desktop 11.04 64 bit, as this may also be given back the HTPC role which had moved away to an Acer nettop during the WHS run.

So far I have tried the following:

Unetbootin + Generic 8GB USB booting as USB
Unetbootin + Sandisk Cruzer 8GB w/ U3 Disabled booting as USB
Sandisk Cruzer 8GB w/ ISO loaded in to U3 via u3-tool booting as CD-ROM

All three options get to the bootloader. Unetbootin shows two of each entry, none work. CD booting shows no menu at all, just a graphic of a person in a circle next to a keyboard, but still seems to try to move ahead after a timeout. In either case, all I get from there on out is a blinking cursor.

Hardware:
AMD Athlon X2 3800+
Asus A8N-SLI Deluxe (nForce4 SLI)
4GB RAM
EVGA GeForce GT220
A bunch of SATA hard drives


Any ideas as to what may be happening and how to solve it?