Running a linux os in a VM like Virtual Box or VMware is not really a good idea for use as a everyday os.
If I remember rightly some functions of an os will not work without some penguin fooey.
If you do dual boot it is a good idea to make a small "boot" partition to put the linux bootloader on. This way leaves the MBR alone and does not disturb its use by Windows.It is recommended to install Windows first which you already have done.
If you do go ahead and try dual booting then for goodness sake do a full clone backup of your Windows install for when things go awry.
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