Preventing execution of viruses or malware on a computing device includes compiling an inventory recordation of legitimate applications and terminating execution of any application not on the inventory recordation while in a protected mode. An instantaneous and unprompted inventory recordation known as a "snapshot" can be performed by the computer program. A user may further train the computer program to identify legitimate applications routinely accessed by the user and to be updated to the inventory recordation, such that the inventory recordation is personal to the user. After training, the protected mode can be activated. A smart icon graphical user interface is utilized, that automatically toggles between locked and unlocked depending on if the computing device is at risk or not, to place the computing device in a protected or unprotected mode.