Then the question is where you have the loader Windows.
Disk I hope?
Put rough on the disk where there are no Windows. And make it bootable.
Rough will find Windows and everything will be fine. It will be possible to load and Linux and Windows.
Now, if the disk is only one. And on it on different partitions are Linux and Windows the operation would be more difficult. And you can break Windows:) to play safe I would advise to take a flash drive (on a gig or two will be enough) and put a rough (and generally the whole boot linux-like) way. And make the stick bootable.
I have done so. Do periodically bekapy stick.
But if the USB flash drive to take more then a stick for example you can even record a live CD of your Linux distribution. And kalindi WinPE emergency run Windows.