Ok so I've seen a lot of confusion lately involving nandroids that don't want to restore so I thought I'd clear up a few things regarding them. First of all, nandroids are exact copies of your current rom, kernel, and all user data that are created through your recovery and are stored on the sd card in a folder called "nandroid". Second, you do not need to wipe to restore a nandroid, I've actually seen problems arise after restoring one right after wiping so don't wipe. Another important issue, if you make a nandroid backup through say Clockworkmod recovery, then you must use clockworkmod recovery to restore it also. Whatever recovery image you are using when you make a backup is what must be used to restore it. Another biggie that fouls up nandroids is when you rename them. Technically they should work fine as long as you don't put any spaces in the name but I've seen issues even without spaces so just play it safe and dont rename nandroids. You can still kinda tell which nandroids you have are which as the name given to them by default is actually the date it was created. You can always use a file explorer like astro to go in and delete old ones, this should be done every once in awhile as A: they are huge files (generally 200mb give or take) and B: nandroids have been known to just flat out become corrupt over time. I'd recommend always having at least one nandroid on your sd and also a rom zip (as an extra failsafe). Also, watch out for how much free space you have on your sd card, nandroids are compressed files that require (temporarily) extra room on the sd to expand. I'd say try to keep at least 400mb free on the sd just to make sure. It's late and I'm tired so there are probably other things to mention here that I'll add in later, happy flashing!