First off it is ridiculous in this day and age that systems aren’t universal. Ranting aside, there is recovery software that can let access the drive. Some has already been mentioned, I have used Recoverit which worked amazingly well at finding lost files on messed up memory sticks, although I did have to pay for it. But honestly the easiest way is to find a Mac, offload your files and reformat your drive. Or if there is space, partition the drive and transfer stuff over. FAT32 is a universal format (most memory sticks come formatted as that), but is limited in file size. exFAT is a newer version that allows files over 4GB, but older computers may not recognize that format.
Hope that helps.