Reactivate Tally 7.2 after a format

In my office, we use Windows 2000 Pro ona FAT32 Partition and use Tally ies 7.2. I converted our C: partition from fat32 to NTFS for security reasons without re-installing Windows( thorugh command line). However, this changed Tally to Educational Mode. I got hold of my Tally CD Box and re-entered the Serial and Key and email id, but it shows this license is already activated. One must surrender it then try again. However there is no surrender option in Tally Menu. So how should I solve this problem as our work is getting hampered. I called the support and they told me to activate it online but it is already activated as shown by the pop-up.