If Windows is in a Bootcamp partition, Time machine will not back it up.
If Windows is just in a Parallels VM, Time Machine may or may not back it up. Lots of times VMs are flagged to not be backed up. You should be able to check the Time Machine exclusions to see if this is the case. You could also just open Time Machine and see if the VM files are there.
In addition to TM, I'd recommend investing in a bootable backup--either Carbon Copy Cloner or SuperDuper are the usually recommended ones. That way if your Mac's hard drive failed, you could boot off the external drive with the bootable backup.
02-01-2015 04:33 PM