Installing Windows on a machine without a CD/DVD drive has always been a bit tricky, and you'd think that "geared towards netbooks" would imply that Microsoft made this process a little easier. Well, they didn't, so you'll still have to resort to some tedious work before you can actually start the installation. It's hard to screw this up, but it's still tedious work, and shouldn't really be necessary in this day and age. The instructions below are taken from garyshort.org.
Get yourself a nice USB drive, at least 4GB in size (2GB is too small, and I'm not sure if 3GB drives exist), and plug it in your computer. Then, load up a command prompt with administrative privileges (right click, "Run as administrator..."), and enter the following commands to properly format the USB drive:
list disk[lists the currently mounted disks, and assigns them a number]
select disk #[selects the USB drive, replace # with your disk's number]
clean[removes any MBR and partition information]
create partition primary[creates primary partition]
select partition 1[selects the just-created partition]
active[marks the partition as active]
format fs=NTFS[formats the partition as NTFS]
assign[mounts the partition and assigns a drive letter]
The next step is to prepare the bootsector of the USB drive so that it is capable of catapulting the Windows 7 installation routine. To do this, put the Windows 7 DVD in your drive (or mount the .iso image using your tool of choice), and navigate to the
/boot directory using a command prompt with administrative privileges. For some weird reason, the prompt I still had running after ceating/formatting the partition on the USB drive no longer had administrative privileges, so I had to load another. Once you're in the boot directory, execute the following command:
bootsect /nt60 #[prepares the boot sector, replace # with your USB drive's drive letter]
The rest is pretty easy. Copy the contents of the Windows 7 DVD/.iso image onto the USB drive. You can do this via drag/drop in Explorer. Once the copy process is complete, you can boot from the USB drive straight into the Windows 7 installation routine as if was a regular bootable DVD. On the Aspire One, this means hitting F12 during boot, invoking the boot menu, and selecting the USB drive as the boot device. Make sure that as soon as the installation routine starts rebooting, that you do not re-launch the installation routine.
That's all there is to it. Tedious, but if you're reading OSNews, this shouldn't pose any problems.