Neoware ca5
True, even if you reflash the system to bring it to a fresh state, it will still need a server to do anything reasonable.
Head over to http://www.neowareftp.com/ and click on the "Tech Support"
link. A password dialog box will show up: [since it may violate TOS here I won't post that info, but it's readily available on the web.] Once in, click on the FlashRecovery link, then pick the flash that relates to your machine - CA5's are usually the CE versions. Download the file.
Now, this program will work on XP systems. Install the program and follow the directions. You'll need either a cheap hub, switch, or a simple crossover ethernet cable. Hook the thin client to one end, your PC to the other, run the tftpd32 program as described in the documentation, set up the thin client per documentation.
If all is done right, your thin client will grab an ip address from the tftpd32 program and you'll see the reflash menu. Pick the number corresponding to the proper reflash, and watch the machines do the rest.
When it's done, you'll have a pristine OS on your device.
now understand, these are made primarily for accessing terminal servers in businesses or schools or hospitals, so it may be useless unless you just want to do some primative web surfing (the CE version has an embedded version of IE5, no java, no flash, and probably no room to put it on that 16meg flash disk.)
But if you buy these devices for a accessing terminal servers, this will give you a clean client.