Setting up Linux in 7480

BACK STORY: 7870

Last year, I purchased a 7470 for use with Linux. The computer worked fine, but it had some kind of weird bug where no matter how little was running -- even just after boot, all cores would just hit the ceiling, slowing the computer to a standstill. I tried more than 5 Linux distros on the computer, and the problem occurred with all of them. After doing some research, I found out that other people were experiencing the same problem with that model. I had figure out a workaround. If I unplugged the power and ran it from battery, the cores would return back to normal operation. But I got sick if intermittently having to pull the power corn in and out, so I just gave up. I put Windows back on it and sold it on eBay. I also purchased another brand new dell for $2000, but I couldn't even get any distros of Linux to even boot on that. So I old it to my mum for cheap. I also purchased 3 other, cheaper, several year old Dell's last year from eBay to see if I could get an older Dell working. I had success, but each laptop came with its own problems that made me not want to use it.

I'VE JUST PURCHASED A: 7480

OK, so the reason I am here is because I have purchased a refurbished (by Dell) 7480. I am hoping that what ever was occurring with the 7470 will not be present with this model. I specifically purchased a Dell (again) because I know that Dell works closely with the Linux community and even swap out chips in design iterations. So kudos for that, Dell.

Anyway, I'm FAR from being a Linux geek. I'm just a regular user (bit of a normy) that hates Windows (for privacy reasons). But I do definitely try to learn and understand. I've only been a full time Linux user for about 18 months. I still have a lot to learn. The reason I am here is to ask if there's anything i should do before I install Linux onto this laptop? So maybe this time it will work properly? My intention is to install Linux Mint -- because after trying many dostros, I've come to the conclusion that Linux Mint is the best well-rounded, functional, hassle free distro.

Should I update BIOS or anything? If so, I have absolutely no idea how. I've just seen people talking about that during my research of installing Linux into Dell computers. I do recall, though, that it can only be done from Windows. So I guess I'll need to keep Windows on it long enough to do what ever I gotta do. 

Is there anything else I can/should do, to prepare it for Linux? I'm here ready to learn. I just want to get a Dell working properly with Linux. Once I get ONE Dell working right, that's what I'll be buying/recommending for family and friends. I still haven't had the privilege of getting a Dell working right yet. I'm very optimistic about this 7480 though!