Odd MD-5 behaviour

[Bumpus]

1. I d/l 7127
2. MD-5 & CRC are perfect.
3. I make a copy of 'known good' ISO.
4. I rerun hash check and it fails on the copied version. Doesn't matter if the copy goes to the same partition or a different physical hd. (all to local pc tho...no network copying)

I repeat steps 1-4 and MD-5 & CRC a perfect on both the orig and the copies. wtf?

OS - similar results in both XP & 7-7100 (dual boot)
APP - Flyingbit Hash Calc & Hashtab

Is this ISO THAT sensitive to corruption?
Would this "sensitivity" lead into the high failure rate when trying to burn the damn thing to a cd?
Am I a total F'up that can't even tie his own shoes?
Was it total horse$hit luck that my usb version worked perfectly the first time?
Does everyone always double check the hash's on copies of their ISO's?
Should I just shutup and get back on the Short bus?

Bumpus

 

[fwc]

what is your working WIN7 MD5?