I have a one year old Toro timecutter ss5000. It has been a great mower until yesterday. I started the mower as I always do and when I went to move it acted as if the electric break was still engaged not letting me move making a grinding noise. i shut down the mower and grabbed the owners manual and I assumed the battery charge was weak so I charged the battery and then it worked for five minutes. i began to mow and it locked up again preventing from moving any where. When I shut the mower down nothing works no click, no electric break release, nothing it wont even crank to start. I have charged batteries, bought new and recharged batteries, nothing....please any help would greatly appreciated. thanks in advance.