Lloyd,
You are right, I am perhaps making too strong a statement. I have only tried this unit with one PC. With the complexities of Windows, it it very likely that others will have problems with other PC's with other Firmware and BIOS's, etc. ...
But...
...I did not just randomly buy this model. I looked up the USB - Serial converter that Parallax sells on their site for the STAMP2 and then fund it for less money on the TigerDirect.com site (while I have nothing against ParallaxInc.com, I have no reason to give them an extra $3 of my money either ;-)
ParallaxInc.com USB to RS-232 conversion device:
Mfg: Bafo Technologies
Model: BF-810
Price: $22.95
TigerDirect.com USB to RS-232 conversion device:
Mfg: Bafo Technologies
Model: BF-810
Price: $19.99
In any case, all I can say is that it has worked great for my on the one PC I have used it on for both the STAMP2 and the EDU RC.
I wish you all the same success.
Joe J.