My Acer Aspire One A1101 only came with 512k of RAM and while that’s probably ample for the installed version of Linux, it’s not enough for my Windows XP installation. The good news is that there’s an extra socket for a 200pin SODIMM in the Aspire One. The bad news is that you need to take most of the computer apart to access it.
As long as you’re somewhat inclined with electronics, this install isn’t too hard, but be forewarned that it will invalidate your warranty, and while I haven’t heard of anyone having problems, could mess up your computer. In total the install took me about 20 minutes and I was moving slowly and carefully. I also followed these instructions on where all of the screws are located, and how to disassemble the system:
You’ll need a couple of very small flathead screwdrivers for prying and a small and a very small phillips screwdriver (there’s one silver screw that’s smaller than the rest under the keyboard). I ended up dremeling a screwdriver to make it smaller and fit this one particular screw. Make sure you’re doing this work on a non-carpeted floor to prevent static.
The only portion that I found difficult at all was removing the keyboard. As noted in the above video, there are three tabs that need to be pushed back, while prying the keyboard up at the same time. I used two small flat head screwdrivers, one to push in the tab and the other to gently pry. Just go slowly and be carefully and everything should come out and go back together smoothly.
The 1GB SODIMM can be found for less than $20 online. You will need a DDR PC2 4200 533MHZ SODIMM (if you get something faster it should just run it at 533MHZ). I found a Kingston one from an ebay seller for $14.50 shipped so shop around for a good deal. After the RAM is installed and the computer is put back together, check the BIOS (press F2 at startup) to make sure that the computer sees the new memory.