If there are files that you want to save to save, back them up and do a fresh install to be sure you have no issues, as I stated before. When you do install this time around, make sure to set up a seperate home partition, this will make things much easier if you have to reinstall at some point for some reason, or you want to upgrade when Mint 5.0 comes out, just make sure that when you make your home partition you set-up your partition tables as follows
swap (logical) -usualy 1 gig is a good size for this so you have plenty room for if it's ever needed
/ (primary) -this is your root partition where all programs and main OS settings will be stored
/home (primary) -make sure that you put the "/" in front home so that it will be seen as the proper partition for your home directory
What I usualy do as a good rule of thumb, is split the space I am using for mint between the 2 patitions, this way there is enough room for apps that I want to install, and files and settings that I want to have available to me. I also use an external HDD for plain file storage, things like music and videos.
I hope this helps you in your venture into Mint, good luck and if you have any more questions just ask, we are very friendly and try to be as helpful as possible here.
Welcome to the Mint side.