You should use a AV boot disk instead. There are heaps of them. Pick one from a security company you like, burn it to a disk or USB on a clean computer and use BIOS to boot from the disk.
Why use an AV boot disk?
Quite simply, this takes the concept of safe mode one step further. Instead of only loading windows kernel modules, no kernel modules are loaded. You now have no pesky prompt for your password (unless you have one on the BIOS, and that probably won't be a fingerprint), and removes the possibility of malware interference. You can also scan for rootkits with another disk.
Another option, if you have backups of all your files, is to nuke from orbit. It's a more certain way of eliminating all malicious objects in your system. You need to weigh the importance of your newly created data against the importance of your data leaking.
You should create the boot drive on a clean computer. I suggest downloading the ISO and using a tool like YUMI to burn it to the disk. Be sure to check the hashes/signatures of the file. After that, set the boot priority to favor external disks, stick the thing in and boot. You should see the boot disk. If not, wipe and repeat.
