As Tachikoma said just remove your old wallet file, then restore the wallet from your seed words.
Seeing as you were using 1.5.6, and are now upgrading to 1.7.2 that is quite a few versions you are jumping, so maybe there are some compatibility issues between 1.5.6 .DAT and 1.7 .DAT files
I had the same issue with 1.5.6 which is why upgraded to 1.7.2
When I restore the wallet, it gets created under .\bash in a folder called ".electrum". Is this ok? What do I need to get it under AppData?