You may want to either make it dual boot, or more likely TRY a bootable CD/DVD or USB key FIRST.
I repeat TRY FIRST BEFORE INSTALLING.
There are VERY limited Games on Linux (store bought). Most do require work arounds (not the best choice if you have kids into them).
Other then the PDF's from the IRS, (which you print out or in some cases can fill out on a Linux pc) THERE IS NO LINUX TAX SOFTWARE. The government set it up in such a way that it is contractually not allowed to provide an open source alternative.
For the rest of the work, websurfing, Youtube, Office/homework, email, etc. Linux works just fine. Personally, if one has kids I would want their games, on THEIR OWN computer or at the very least installed under their user name (no connection with pc that has tax/financial info on it). I've seen enough issues over the years when I gamed, of people screwing up their systems.
I would recommend, as this (if I remember correctly) is due to your old pc dying, that you find an old pc, that someone is giving away, if you want to go full install first, BECAUSE there IS a LEARNING CURVE (STEEP FOR MOST that started with Windows).
Linux was started by an individual as a college project, using software from GNU. He let people play with it, and worldwide development ensued. While companies (Red Hat, SUSE, etc) put together versions, individuals can put together their own, it isn't under the control of one company, lots of places to get it. Primarily, that is the reason it is so much cheaper. Lots of people developing what they need and use and doing so in a way (licensing) that they give back to the community and people either pay who they want to reward, (buy a prepackaged) or can make their own or get a free (cost) version. But this shouldn't be confused as it isn't about price, but about freedom of choice.
“Free software” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech,” not as in “free beer”.
Linux is NOT Windows. While a lot of us who use it, call and consider it an upgrade, it is NOT an upgrade as your used to. It wouldn't be any different if you were asking about switching to Mac (your old software wouldn't run on it), without other parts. I hope this helps.