I am using the IOGear USB PDA/Serial Adapter GUC232A ($39.95 at Micro Center) on an Abit AT7 legacy-free motherboard with Windows XP Home.

Here's what I did:

1. Plugged the adapter into the USB Port. Computer responded with "Found new USB Hardware".

2. Put in the CD and told it to search for the driver. It loaded exactly 2 tiny files: serenum.sys and serport.sys. BTW, it warned me that they were not signed for Windows XP. I hit OK.

3. It assigned it to COM3 by default, which would probably be good on my other computer (the one with 2 "real" COM ports), but Touch Screen Setup wouldn't find it.

4. Having read the other threads previously, I knew that the only thing that it really cares about is being on the lowest free COM port, preferably COM1 if you can do it. So, I went into Device Manager. (Hit Win-Break to get My Computer Properties, also available by hitting Start | Right-click My Computer | Properties, then go to the Hardware tab and the Device Manager button.)

5. I dropped down Ports in Device Manager and it was showing "ATEN USB to Serial Cable (COM3)". I double-clicked it.

6. I went to the Port Settings tab and then clicked the Advanced button. In there is a COM Port Number drop down listing every available COM Port number (COM256 anyone?!?), so I selected "COM1 (in use)". Now, I know it wasn't really in use but Windows proceeded to ask me "Are you sure?" about 2-3 times and I kept saying Yes or OK or whatever. And it took. Now it still said COM3 on the Device Manager page but when I double-click it says COM1. (After closing and reopening Device Manager it's fixed now.)

7. I tried Touch Screen Setup again and it worked without a hitch.

Now, since Windows XP has the same Advanced button on my "real" COM Ports on the other computer also, I'm wondering why these instructions wouldn't work with any USB-Serial adapter.

Anyway, there it is step-by-step. Hope it helps somebody... :)