slow mac book pro

Hi there

after a disk crash I had my hard disk changed (I fitted a new 1 Tbyte disk), made a fresh

installation of my Snow Leopard and copied back my Time machine back-up copy of

my old disk. I did this as the "recovery from time machine" procedure kept on crashing.

Ever since, my Mac has become exceedingly slow, often becomes unresponsive... it

has become a nightmare. I had my disk verified and it looks ok. I had my permissions

verified and repaired. Still some of them would'nt get repaired.

What can I do???

Thanks in advance

Francesco