15″ MacBook Pro Unibody i7 upgrade RAM & replace failing HD. Permanent errors on hard drive but managed to repair temporarily and recover all data. 2 x 4G RAM fitted, new drive & data recovery completed. NB we have software to test integrity of drives in more detail than Apple’s Disk Utility. Sometimes a pass in Disk Utility does not mean the disk is OK as experienced by this client. Symptoms are slow performance and poor data transfer speeds.