Bootable USB device with anti virus

Hello Donald,
We are sorry to hear about the inconvenience caused.  We would request you to have a look at the steps in this article ( http://support.avg.com/SupportArticleView?urlname=How-to-remove-infection-from-partition-table-or-boot-sector ) to run AVG Rescue CD. Thank you.

My daughter started a new notebook, and I beleive the Geek Squad from Best Buy left a virus on it.
The virus is a block, meaning that you can not do anyting on the internet, such as download an antivirus, plus blocks any mehtod except their own to get it off, I am surprised they have not been hit with criminal or class action suits.
AVG had me set in safe mode, but after using MSCONFIG, I can't get pass the password when booting.  THe guy on phone gave up and said too bad, it is my problem.
I only wanted option #3 below.
The only three ways I can think of getting the virus/trojan off is by
1.  Getting a restore disk and reinstall windows, I can't access drive to do so.
2.  Pulling notebook drive out of computer nad putting in my desktop to scan…  would void warranty.
3.  Creating a bootable usb (no CD on notebook) with virus scan on it.

So, for #3, how do I do this, I see that there is an iso (AVG Rescue CD), I put on USB but did not boot.  I can use RUFUS to burn to flash, but will not boot on notebook, after making the USB the boot drive.

Help please.

Is there a good set of instructions for this?

Hello Donald,
We are sorry to hear about the inconvenience caused.  We would request you to have a look at the steps in this article ( http://support.avg.com/SupportArticleView?urlname=How-to-remove-infection-from-partition-table-or-boot-sector ) to run AVG Rescue CD. Thank you.