PSP Downloads | 5.03 Firmware Update
PSP Downloads | ChickHEN Homebrew Enabler R2
First Update to 5.03 ofw. Then install ChickHen R2 (This will take a few - many attempts to get ChickHen on your psp, you may have to reset the psps system settings leaving the psp name as default (Turn off Umd Cache if slim)).
Next install Pspident to the psp and run it. Tell us what it says.
PSP Downloads | PSPident 0.4
From that info you'll be told to either install Cfwenbler or 5.03 Gen-b (If it's a nonhackable slim or 3k psp)
Or you'll be told to use Hellcats Recovery Flasher V1.60 if it's a Fatty, or a hackable slim
PSP Downloads | Recovery Flasher v1.60
PSP Downloads | 5.00 Firmware Update (this goes in the Hellcats recovery flasher folder)
If you have a phatty or a hackable slilm Hellcats will install 5.00m33-6 cfw to the psp.