I've basically loved Guitar Hero II since I picked it up a few days before its actual release in stores. I've been enjoying my time with the game and was just about to start hammering into the Hard mode (remember, this is my first experience with a GH game, so I'm starting off from scratch) this weekend, but it was not to be.
I had 3 songs left on Medium (Madhouse, Psychobilly Freakout and The Trooper I believe) to get 5 stars on to unlock that achievement plus whatever guitar is unlocked as well. On Thursday night I decided to delete the band that I had set up so a friend could play the game. Chances were they wouldn't be back to play the game since they got it themselves, so I deleted the band through the menu and shut off my Xbox 360. When I came back to the game on Saturday night I turned on the game and it locked up at the "Loading" screen. My initial fear was that my launch system was getting close to a 3-ring death and I just wasn't prepared to pay the money to have my 360 fixed or replaced. Before going into full meltdown mode I decided to go looking on the internet to see if other people were having the same problem. It seems that it is a "flip of the coin" chance that your save can become corrupted if you delete or change a band. Well, I flipped the coin to where it corrupted itself, so I had to start all over again.
It is excruciating to go through the Easy mode again, but I started with that. Easy is just so slow when you've spent most of your time in Medium and I expect to feel the same about Medium as I go into Hard and Expert. I went through Easy just to unlock the guitars for finishing it and getting all 5 stars. Then I started through Medium and am about halfway through now. I believe I am getting better scores than I had before, but I also remember I had at least 12 perfect songs in Medium (this includes Xbox Live downloaded and purchased tracks from the Store in-game). My goal is to at least duplicate that, but we shall see.
This whole thing is a bit frustrating though with having to go through it all again instead of being able to continue from where I was. In the end, the moral of the story is to be sure to copy your saved game to a memory card (if you have one) for backup purposes. I still love this game, but we're going through a "difficult" period at the moment.