Re: upgrade
I've been hearing that the new update is screwing up grub2 on some multiboot systems making it so you have to either reinstall Linux or fix grub before your able to boot back into Linux
That's been a common issue with Windows installs, not so much updates pre-10.
Boot Repair Disk is a small ISO you can download and install on USB or CD/DVD which does a pretty good job of repairing these things. I've had to use it from time to time to fix other systems. Quick, straightforward, and effective.
Tweetiepooh has a decent idea - putting Grub on another disk and setting the BIOS to boot from that normally. I have been known to go one further, disconnect the Linux disk completely so that no matter what Windows cannot touch it.
Biting the hand that feeds IT
