Why does my MacBookPro start so slowly?
Is it possible to speed up my computer? It starts very slowly, but the working speed is all right.
MacBook Pro, OS X Mountain Lion (10.8.2)
Speeding your macbook back to more normal speeds can sometimes be achieved by clearing cache repairing permissions and resetting your computers pram
1: Clear user cache
http://osxdaily.com/2011/12/08/delete-user-caches-in-mac-os-x/
2: Repair permissions
http://support.apple.com/kb/HT2963
3: Reset PRAM
http://support.apple.com/kb/HT1379
For a more permenent solution you could also look into installing a solid state hard drive (SSD) in your computer, this will also significantly improve startup and program launch speeds