I have two HP desktops. On both of mine as you are booting tap the escape key until you see a Loading message on the screen. You do not need to change the boot order. You will get a list of bootable devices. Select the usb device you plugged. I can't imagine the laptop being different if it is an HP. Now the bad news. I have the Homeland Security ransomeware on one machine. I could not get a memory stick to boot completely. One did, but lacked the Linux config file. I switched to using a CD and created an ISO file, first for COMODO. It booted ran and cleaned a bunch of things. Sadly, problem still exists. I think tried ANVI. Same results. This trojan is really a pain, as you cannot boot into safe mode. I don't know how I got it, but the first symptom was no internet pages loading. When I rebooted, the trojan took over. I run AVG free version 14 and keep it up to date. I also run Malewarebytes once a week. In the 6 or 7 years I have had this computer (XP Pro), I had one other virus that AVG didn't detect, but Malewarebytes cleaned. My next attempt is to create a CD for Malewarebytes. Maybe I will also try Kaspersky I am getting pretty close to using Knoppix to copy my data and reload the XP image which will wipe the hard drive (ouch!).
