If your Sony PSP (PlayStation Portable) won't turn on when you flip the "On" switch and you don't have a boot disc available, you can fix your issue by performing a "hard reset." This will reset the memory of your PSP, fixing any errors that were preventing it from turning on and allowing it to boot once again. Beware that performing a hard Reset will revert your PSP back to its original factory settings, losing any changes that you've made.
Plug your Sony PSP into its power adapter. If your battery has lost its charge (which you cannot tell because the unit won't turn on), this will allow the unit to have the power it needs to perform the hard reset.
Hold the "Power" switch on the top of your PSP in the "Up" position. This is the same position in which you set the switch to turn on the device.
Continue to hold the "Power" switch in the "Up" position until your screen flickers. Release the "Power" switch. The hard reset has been performed and the unit will now boot as normal.