I have a Lenovo laptop (work issued) that I would like to connect to my home desktop to use dual monitors (I have dual monitors at work, and my job is so much easier). My home pc is an Acer Aspire All-in-one Z5600 desktop that does not have a video port. I read online that I need a USB video card, so I purchased this. This adapter has USB on one end and VGA on the other. I then purchased the VGA cord and plugged one end into my laptop and one end into the adapter. I followed the install instructions (installed onto Acer home pc) and now it's installed. When I try to "extend desktop" from my Lenovo laptop, it won't recognize my Acer home pc. My Acer home pc has Windows 7.
You can't use any laptop screen as a second monitor for another PC since there is no way to feed a video signal IN to the laptop screen, the laptop can only send a video signal OUT via it's VGA-out port if it has one, or via the USB video adapter if the laptop has no VGA-out port.
You need to either buy a second monitor and connect it to your laptop's VGA port (in which case you don't need the USB video card), or buy a second monitor and connect it to your Acer Aspire All-in-One using the USB video card.
Basically, you've misunderstood what the USB video card is designed to do.