At present all hardware SHOULD be giving the user a way to deactivate secureboot, microsoft allows vendors to do evil things and sell products where secure boot can't be turned off but I don't think any sellers of non-tablet devices have yet stooped to such lows.
If you try turning off fast boot within windows control panel, deactivate all hibernation options in windows and then restart, quickly tapping on the relevant key (most computers use f1 or f2, without the function key held at the time, but if you stated your exact model number then the exact key to use could be found online). The BIOS should in theory then open, you will probably have to navigate with arrow keys but some types of BIOS/UEFI support mouse use too. Check across the tabs one by one and see what options you have, as well as disabling secure boot make sure to change the boot order to put your USB drive or CD/DVD drive (depending if you are doing a live USB boot or a boot of linux by optical disc. When you leave make sure to save your changes.
I also found a finding at https://forums.lenovo.com/t5/ThinkPad-S-Series-ThinkPad-Yoga/Disabling-Secure-Boot-on-Thinkpad-Yoga-S1/td-p/1794341
suggesting you might need to make other changes in the BIOS to preserve changes you make and ensure secure boot isn't re-enabled. Namely you might need to disable "OS Optimized Defaults" so your changes will be respected.
Another option, probably present, would be to turn on the CSM legacy boot setting, windows will probably not be able to boot at all when this is set, but linux should be able to boot. If you ever want to boot windows again later you would have to turn off the legacy settings and go back to the default modern UEFI type of booting.
Bitlocker, if it is on, will mean that once linux is booted you won't be able to read your hard-drive from within it, as the harddrive will be encrypted by it. But if you want to say goobye to windows you can still install linux onto the drive and wipe away the encrypted stuff, far more sensible would be to, if upon live booting linux you find the hard-drive encrypted, boot windows again and see if you can turn bitlocker off.
Bitlocker or viruses are unlikely to be the cause of your current problem. While updating a BIOS/UEFI might occasionally help these sort of problems if a manufacturer has made changes to improve linux booting since the original BIOS that the machine came with, it can be tricky and very often the fixes made to the BIOS/UEFI are not the kind of thing that helps linux users. The person at geeksquad probably just heard the word linux and got confused from there onwards, then fell back to a script of questions and answers and began on blindly recommending updates* and blaming viruses* without really knowing about the cause of the issue. Be glad you've found this forum, there are real experts here (I'm not one of those top experts, I just know a little bit and try to help where I can) who know all about linux and how to get it working.
*not that some updates don't fix some things, and not that viruses don't cause many problems, but your problem doesn't sound like either
Edited by rp88, 15 February 2018 - 06:36 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB