BSOD - shieldf.sys

Hello

can anybody help me?
I experience regular blue screens of death with the message STOP and
reference to shieldf.sys
This is since i have installed Ayrecovery.
I intend to register this prorgam but 1st i must solve this shieldf.sys
problem.
Seems to be uses by RxRecovery??? That made me think of Ayrecovery as
the cause.

Thanx

Ray