There are multiple "share-ware" applications out there that do this. A quick Google search will list many. I won't list them as I haven't used them and won't/can't personally recommend one.
What I will recommend is utilizing the Administrative account as it was intended. You should be running in the "least level of privilege" account possible and modify your application permissions to only allow admin to run it. Then use "Run as Administrator" to run what you want to use.
The fact that you are in an Admin account will subvert the purpose of folder locking as it will be easy to get around...