I recently updated my computer with a memory upgrade and a clean install of Win7 64-bit (used to have WinXP 32 bit). For some reason I am having continuing issues with one of my drives having a bad cluster issue. It is a 2 TB drive that contains all of my documents and multimedia. Whenever I try to back it up to a NAS, I get semaphore timeouts on ~10 files (out of probably 100k files). I run a scan disc on the next startup, and it finds and repairs the 10 files saying they have bad clusters. Next time I run a backup same issue with a different small set of files, same fix. I believe this issue is starting to lock-up other applications that use files on this drive as well. I have updated all of the drivers for the entire system as well as the BIOS and it didn't address it. I thought it was just a bad drive, so I bought a new 2TB drive from another company, and am now facing the exact same issues with the new drive. Any other thoughts what might be causing this? Does this sound like a bad MOBO? Just strange it would start right after the upgrade. Let me know if I need to post any other information, appreciate the help!