[Solved] AAO D250 - Can't access boot menu

Hi, new to the forum.

I have an Aspire One D250 on which I'm trying to dual-boot XP and Ubuntu 10.04 Netbook Edition. XP is already installed, and I'm trying to install Ubuntu with a 4GB USB drive. I used Netbootin to prepare the flash drive with Ubuntu, but can't get the Aspire One to boot from USB. At startup the screen reads "Press F2 for Setup." I do press F2 but the machine basically ignores any key presses and proceeds to boot into XP. I've even tried holding down the F2 only to be greeted with a shrill beeping. I've tried any number of combos - F12, Esc, Del, even added various "modifiers" to the sequence (Control, Fn, Alt, etc). I recently clean-installed a fresh XP Pro onto an empty upgraded HD (from 160GB to 500GB); it appears the only way the Aspire One will boot into a secondary media is if there's no system present. I can't conceive of wiping the drive and starting from scratch, and I'd really like to dual boot Windows and Linux. I'm wary of updating the BIOS based on mixed results from posters here and even Google results :? Can anyone help or explain why the D250 refuses to boot from USB, or why I can't even access the menu? BIOS is OOB, never been altered or updated...the process should be straightforward, but is there some type of "lock" or restriction having been put on by the factory, or is there something else I'm missing?

Edit: I am now able to access the F12 boot menu. I downloaded the latest BIOS from Acer.com and opened the flash program from the desktop. Should work well from now on. I guess the factory settings were for some reason blocking the menu. (Which is good, in some respects, since improper use of such programs will "brick" the system!) I appreciate the wealth of content here and am thankful that with a gulp and crossed fingers I am able to push forth with the install!