Hi,
Is this a new monitor, or did it just stop working?
Your post is a bit confusing. Are you saying you tried the CY199 on two computers and it didn't work? If so, I'd have to say it sounds like the monitor is faulty, the cables are faulty, or it's not connected properly.
And what do you mean when you say the "other model # YP999"?
Here's a link to download the users manual, and look at the product support......
http://www.i-inc-usa.com/Product/cy199.htm