Locked out of a user folder

Hi,
I was attempting to find a way to have my family of 5, be able to each have their own individual accounts (as admins) but made so they couldnt access each others files in the C drive.
So I decided to mess with the security settings tab under properties of the users folder, and I edited permissions for the adminstrators which i thought would cover everybody else using the computer.
Well, for the first two tries I edited the admins and unchecked the Allow Checkboxes for full control, modify, read etc. That was all I did.
But for the third account I tried unchecking the allow and then clicking all the deny checkboxes.

Now my problem is that I can even access it as the user of the profile because he is an admin as well.
The other method where i didnt click deny, works fine and keeps other people out and lets you in. even though it gave me a system warning of consistency...

But now i cant even undo what i just did because i basically have no power whatsoever to change the security settings or delete the profile.

We just got this computer so its not a huge loss to make a new one, but it will be annoying to have the old folder always there in the c drive.

Anyone know of any way to fix this or get beyond the blockage ive made?

Thanks Brink, It worked grand.
I completely forgot about System Restore.
Had an access point from the morning of the event.
Thanks again,
Josiah