My macbook pro hard drive seems to be corrupted, should I replace it? I have a 2,26GHz  mid-2009 macbook  pro  with 8Gb Ram and mountain  lion (mac os x 10.8.2).  Recently  my  computer doesn' t  stop freezing  and  I have to force the computer to shut down. Then  I cannot boot  at all the computer shows a flashing folder with a question mark. When I run disk utility from the installation cd then I am able to boot from the drive again but it will eventually starts lagging  after a few minutes of utilization with software's such as safari, skype or even the finder. I wanted to get a ssd recently. Will it fix this issue or the problem might lie elsewhere? I tried to boot from different sessions it always freezes at a moment, I have been able to run a virus scan disk and I didn't  find any virus nor trojans .
I changed the sata cable of the drive and it is working fine now.