accidently connected HP compaq6000 charger

Not sure which Compaq 6000 AC adapter you used, but it looks like you tried to charge a 5V device with something around 18+ volts. I would imagine that there are a few possibilities. First the battery, you definitely want to replace it. Second, check the fuses on the PSP and see if they did their job. Check with a multimeter for continuity (hopefully it is blown) also check for any burned, charred components. Pay good attention to the charging and the power IC. At this point it is pretty much a guessing game until you have the PSP disassembled and evaluated the damage. Check on here for more information on the fuses. Hopefully all you need is one of these fuses. Here are the guides for your device which should help you with the disassembly. Hope this helps, good luck.