Printer will not print

I have the HP deskjet F2100 series
HP deskjet F4100 series,

I bought the printer/copier/scanner in April and it worked fine until 2 months ago. I uninstalled and re-installed to see if that would correct the problem. This is what appeared in the window ''Driver not digitally signed or not signed in the appropriate manner. Contact hardware vendor''. I am just furious after spending hours uninstalling and re-installing. Please tell me what I need to do. I bought this at Best Buy.