my unit that I bought in January died on me about 2 months after I bought it. My replacement has been totally fine though.

Mine worked fine up until 2 days ago. We had a small storm pass through with lots of lightning. When I went to place the next day, nothing will load. Eveything freezes up on the initial logo/loading screen.

Thank goodness I popped for the extended warranty last month - I called MS and they had me try without the hard drive, but the problem is still happening. Looks like I'll be calling today to get this repaired.

It is not, the Terms and Conditions state that you need to provide a request to change the warranty coverage to your replaced Serial Number in writing; however, Microsoft sent a letter with my replacement stating that the changes had been made for me and I had no problems when I called up to report that the replacement unit was overheating.