i dunno if this is posted anywhere but i couldnt find it. my psp wont connect with my computer or ps3. i am running windows vista on the pc and 5.00m33-6 on a 200x series psp with the ta-88v1 motherboard just ask if u need ne other info.
Check the VSH menu or the recovery menu to see what device is set to be the USB device. It should be by default the memory stick. I can't think offhand what else could affect it software wise. Anything else must be hardware so you may want to give the USB port a clean or perhaps even try a different USB cable