Vista - Lexmark X9350

I have a Lexmark X9350 All in One Printer. It is Vista compatible (at least
the box and documentation say so) and can be used wirelessly. We had the
printer hooked up to our desktop (Windows XP-SP2) via USB. My husband
purchased for me an HP Laptop with Vista on it. I installed the Lexmark
Printer and originally installed it using the USB connection but felt that
was silly since I had a wireless card on the laptop. So with the help of
Lexmark, I adjusted the settings to have the printer work wirelessly with the
laptop. It was working wonderfully for awhile but then all of a sudden I
started getting Printer Communication stopped working and has closed
messages. I contacted Lexmark several times and still getting the messages.
Finally yesterday, I uninstalled the printer and then
reinstalled...everything looks good, I was able to print the test page, but
this morning I noticed the error message again. I'm at a loss here and
really don't want to change printers - I happen to like Lexmark products.
When I did a search for the file listed on Lexmark drivers page for this
printer on the computer, it didn't find it. How can I determine which driver
file IS installed on the laptop? Has anyone had this problem and if you did,
how did you solve it?

Thanks so much,
Dawn