Go to Safe Mode, log in to the account you want to access the files from.
Select properties of the desired folder and navigate to Security tab, with a bit of fiddling around you should be able to set the ownership to your current account. After confirmation, it would apply properties and the dialogue box's title should look something like - taking ownership.
You should be able to access the files/folders now.
EDIT:
Looks like I was too late to reply