When I insert a new UMD i get the game could not be started. 80020148. The UMD is recognised and the thumbnail appears on the menu, but the game will not start. Please help.

Solution: 1) You must first backup ur data on your memory stick to your PC. Mainly the saved games data. ( directory is PSP\SAVEDATA) 2) Format the memory stick using the PSP format tool in system settings...not your PC. 3) In System Setting UNCHECK or UNSELECT "UMD Cache" this must be off!!!! 4) Connect your psp via USB cable 5) Copy your game saves / data back to your psp remember >> PSP\SAVEDATA . 6) Do a hard reboot of your psp ie hold the power switch for 3 seconds and it will reboot. 7) Your UMD games should now work with no probs.