How can I install Linux (Ubuntu) onto a 500GB hard drive

I want to install Linux (Ubuntu) onto my second HDD on my laptop. So I run windows 7 currently on my active Hard Drive on my laptop. I do however have a second hard drive that is connected (currently locked and can easily be unlocked). I was wondering, without reformatting my current OS drive, if I could safely put another operating system on my second drive? And if I could, how can I switch safely between the two. There is a lot of information on my primary drive that I currently run and I do not fancy backing it up and making an entire copy of it. Though I am not beyond reason. My laptop is an ASUS G74S, comes with a dinky "sub OS" that can go into windows with the click of a button.

Any help would be greatly appreciated!!

Thanks,

Bobbby103

Install the Linux OS on partitions with no data. If you don't have any such partitions, consider making one by going to disk management and choose to shrink partition that is having enough space and some amount you can use to create a new partitions, that is between 100-150 GB (little lower will also work).

Good luck though!!