Could today's Windows update have caused boot problems?

I have a 64 bit box that is dual boot Windows 7 64-bit and Ubuntu.
I booted into Windows today and saw the 'updates ready' sign on the shutdown button so I clicked to let it install. It took a while to install 2 updates.
Then I rebooted, but now it doesn't get past the motherboard splash screen. So I don't even get the disks found messages or let alone the prompt to choose Windows or Linux.
Could this be caused by the updates? Seems weird for a Windows patch to have consequences beyond the Windows OS, but it seems unlikely to be a coincidence