Hi,
You would probably be better off using your Lexmark installation CD..
You should be able to get it to work by setting the Compatibility Mode of "SETUP" on the Lexmark installation CD to Win 7 or possibly XP SP2 or 3 depending on how new the model is.
It probably has more features than anything you will download...mine turned out that way.
To find setup on the CD, select Open or Explore instead of just running it.
Then right click on SETUP and select Properties...Compatibility Tab is at the top.
Part way down is a Compatibility Mode check box and a drop down option list.
I used XP SP3 with a X5340 and it worked.
IMPORTANT...
If you have previously tried to install the printer, REMOVE it from your system in Devices and Printers before uninstalling and reinstalling the software.