Printer Setup, Software & Drivers

I have searched all over the community forums for a solution. My HP printer used to support automatic duplex printing, then one day it stopped. This happened after I updated it to the HP Smart Start.  Now, it only does manual printing, where I have to flip the pages over.  I don't have time for this when printing large documents.  The alternative is costing me a lot in paper.  After uninstalling the device, all the drivers, etc., and still receiving the same results, I discovered on another post that the new driver HP has on the product support page does not recognize (or detect) the driver to auto duplex print.  The only alternative is to install the drivers from the installation CD. I have no idea where mine is.  There has to be another way to fix this? Can I install drivers from a different model?  I cannot repurchase the CD because it is not available on the product page website for order.  The virtual agent will not connect me to an agent since my warranty is expired.  When I try calling tech support, the automated system will not allow me to reach an agent without a warranty OR a case number from the virtual agent, which I am guessing you cannot get without a warranty.  Why is there not an option to pay a la carte?  I need to print documents and need immediate assistance, and all I can do is come here? How do I fix this issue because I'm at my wit's end? It would almost be easier just to buy another printer, which is ridiculous since my current one works just fine. I need help with correcting this driver issue.