Strange security popup at boot

[Richard in AZ]

A friends new Gateway computer pops up a dialog box.
The dialog box is basically blank except in the title bar it states "Security Checking" and has the red X for closing
Then in the body of the box is a space requesting a password
Then below that two buttons "Okay" and "Cancel"

The computer has Windows Vista Home Premium.
He removed the McAfee software and install the Free AVG and does not believe he has any other security software.

He does not have a password for use of the computer and when he chooses "Cancel" the computer seems to work just fine.
Anyone have any ideas where this popup dialog box is coming from.

I have not seen his computer, but he sent me a screen shot of the dialog box and is asking for help.

 

[Danny Krychek]

A friends new Gateway computer pops up a dialog box.
The dialog box is basically blank except in the title bar it states "Security Checking" and has the red X for closing
Then in the body of the box is a space requesting a password
Then below that two buttons "Okay" and "Cancel"

The computer has Windows Vista Home Premium.
He removed the McAfee software and install the Free AVG and does not believe he has any other security software.

He does not have a password for use of the computer and when he chooses "Cancel" the computer seems to work just fine.
Anyone have any ideas where this popup dialog box is coming from.

I have not seen his computer, but he sent me a screen shot of the dialog box and is asking for help.

Just on a chance, tell your friend to download and run Malwarebytes.

http://www.malwarebytes.org/