My psp won't recognized by the computer every time

Well does your PSP recongnise other PCs?
Do you have other MSs?
Try other USB ports.
Try other PCs.

So it won't show up when you plug in your PC.. or... does anything pop up when you connect your PSP to your PC?

If this doesn't work, take it to SONY. If your PSP is still under warranty, then the repair is FREE.
.. wait, did this MS come with your PSP when you bought it?