This one doesn't seem to be related to your earlier one. I would suggest that you may need to get back to the basics. Confirm all drivers are updated and current as well as the MoBo Bios. Check the physical components and connectors, especially the hard drive connections on the drive you just replaced, loose or bad connectors can cause similar issues. Reseat your memory modules. Find the specifics on your memory modules from the manufacturer (timings and voltages) make sure that they are configured appropriately in the bios. If you are overclocking anything set it back to standard defaults. Download and run a memory test utility or use the one built into Windows 7. Chkdsk you hard drive. Check cooling, determine operating temperatures...