My HP 12C calculator is brand new. When I put in 240000 and press PV - it just goes blank - as if it turns itself off. It gets off with similar use of i and n buttons. Then when I turn it back on - it says PR Error. I have done a f Clear Reg and f Clear FIN. It seems to need to warm up or something before it starts working correctly. If it were low on batteries, there should be an asterisk showing that it is low on batteries... correct? What could be wrong?
The low battery indicator isn't reliable on the newer 12c. Your description is very indicative of what happens when the batteries are low, so that's the first thing I'd assume. It's also quite possible that the unit you purchased had been "on the shelf" long enough that the batteries it came with are already low due to self-discharge.
Purchase some new brand-name batteries for your unit and let us know if that takes care of it!