2005 prius with 130K miles, no dash lights & would not shut down

Hello, I'm sure someone must have encountered this problem before & can give me some info.

Background: I have driven my 2005 Prius for 130K reliable, trouble free miles. Recently I'm driving 150 miles per day. The check engine light came on every so often & went off again. My 12V battery was dieing so I replaced the 12V a couple of weeks ago with a Yellow Top. I expected the check engine light to go off but it continued to come & go. I bought a scanner & pulled DTC P0420. This was on saturday & I haven't had time to address the Cat yet.

I work nights & drove to work sunday night with all of the lights working properly. When leaving work (still dark) my dash lights would not come on. Tried to shut off, so as to reset when I restarted, but it would not shut down. Checked all of the usual settings, still no dash lights & no fuel calculations. Went to get gas & it would not shut off. Drove home, still no dash lights & no shut off & deck lid would not unlock. Drove an additional 70 miles round trip to take wife to work & it DID shut off when I got back home, also deck lid finally unlocked, still no dash lights.

Any suggestins as to where I should start would be greatly appreciated.