Slowed Down!!

I have been so proud of my new PowerBook 15-inch G4. It has a great sleek look, the OS is much more appetizing to see and use, and the whole package seems 5000% better than all PC's. I have recently though (it is only 1.5 months old), noticed a large decrease in operating speed, and I'm fretting big-time. If anyone has any suggestions as to why this is, and what I can do to fix it (download a specialized application, etc.) please let them be heard, as this is frustratin me a great deal.

Thank You.

:doctor:

i'm not sure, but i think it would be best if you repaired permissions, go to applications, utilities, disk utility, click on your hard drive, and then click repair permissions

Thank you, what does this do?

Tried MacJanitor?