"No bootable device" Boot Camp error after updating Mac

So upon attempting to boot up to the Windows partition I got the "no bootable device" error, and upon starting up my computer by holding Option the Windows partition doesn't even appear. I understand that this is a common error resulting from an improper installation, but the problem with my issue is that the Windows partition was working fine up until I updated to Yosemite 10.10.3 on the Mac disk.

The Windows files are still there and "BOOTCAMP" is still visible in Finder, but it's not visible in the startup disk manager. I really don't want to have to reset my installation because even though I can retrieve the files it's still going to be a lot of time lost (especially in terms of trying to get my so-called one-time activation software codes working again)...