Strange one this. I have a Macbook Pro Late 08 4GB Ram 2.53 GHz Bought a new OWC Mercury Extreme SSD. First had these issues after installed internally, lots of spinning ball would not start up at all sometimes not the quickness you would expect from an SSD. Anyway sent it back, they did all the updates checked everything and sent it back to me. In the mean time i got an external enclosure with double usb power etc. When i got the SSD i installed Mac OS on it externally got it upto where i needed all ok no problems at all. Now once its back inside the Macbook Pro in the HD bay all the problems again. Out to the external fine again. So obviously not the SSD. My normal HDD works fine inside the computer. Any ideas?