Hey guys. I am new to this forum, but have used these forums for information to fix Jeep problems and motorcycle issues before, so I know you guys are the ones to ask. First, yes I did search, but my computer isn't working at its best right now so it proved quite difficult. That said, I am sorry if I overlooked the answer in another thread. Here we go. I have a late 2008 2.8 Ghz dual core iMac, EMC 2211. About 5 years ago I replaced the 320 GB HDD with a 3 TB Barracuda. It crashed once about a year after I got it. It was under warranty so other than a little frustration of having to swap them out again, no harm/no foul. About 3 weeks ago it failed again. I knew it was coming because it was running really slow and exhibiting some of the same signs it did when it crashed prior. I used an old version of Tech Tool Deluxe to scan the HDD and I received the following failures: Volume Structure, Drive Hardware, Format Check and Directory Scan. I backed everything up, and did an erase, reformat hoping something had just become corrupt. It turned back on, ran really slowly through the first set up software updates. Then it restarted and wouldn't turn back on. I opened in recovery mode and used disk utility. My disk wasn't able to be verified. At this point I just decided to replace the HDD with a 5 TB WD Black drive that I found on Cyber Monday. Yesterday I installed the new drive, zeroed it out, formatted mac journaled (extended) and installed Snow Leopard. It was the only install disk I had available. Now it turns on and works but is exhibiting very odd behavior. I ran Tech Tool again. This time I received Format Check, Directory Scan and Volume Structure failures. I know Tech Tool isn't the best, so I went into disk utility and everything was fine. I then did an apple hardware test and everything checked out fine. I went through all of the updates thinking I would upgrade my OS to El Capitan, to see if maybe the failures were simply due to incompatibilities of having an 8 year old version of OSX, but I can not connect to the app store. El Capitan is the newest version my computer will support. Whats wrong? Is it possible that this HDD isn't compatible? What else could be causing those failures in Tech Tool? I am not able to find anything on the internet and every time I attempt to go to the apple support page safari freezes. I know that doesn't make a lot of sense, but literally every website works but the apple.com and apple.com support. However, those pages work perfectly on other computers in the house.