Hi,
1) We suggest you to restart Windows in the Safe Mode and uninstall Veritas drivers using 'tapeinst'.
http://seer.support.veritas.com/docs/199881.htm
2) We would then suggest you to install the latest device drivers for BE v9.1.
Please refer to the following Technote to download the latest device drivers:
http://seer.support.veritas.com/docs/273853.htm
3) After the installation of the latest device drivers, if the Blue Screen appears again, uninstall the Veritas device drivers through Safe Mode and install OEM drivers.
Please refer to the following Technote on how to use OEM drivers with Backup Exec:
http://seer.support.veritas.com/docs/253974.htm
Hope this resolves your issue.