If you have old files saved in obscure formats, it can be difficult to find a program that will open or convert it. Even if you do manage to find a program that could recognize your files, it could very well cost you. Fortunately there's a free site that can point you in the right direction: OpenWith.org.
OpenWith.org has compiled a massive list of known file types, and will show you what programs will open them and/or convert them. Best of all, the programs that it recommends are all free alternatives to otherwise expensive programs.
If you have files stored on old media like floppy disks, Zip drives, or even CDs and DVDs, it's important to move them over to a hard drive or the Cloud. It's equally important to back up these files using the Peter Krogh's 3-2-1 backup strategy: 3 copies, on 2 different forms of media, with 1 copy off site. Find out more about this backup strategy at dpbestflow.org.