In many cases, games have to be stored in the internal memory in order to be able to play them on the PC. I assume this is also the case here. The USB connection would be too slow for this. However, you can move other things like photos and videos to it to free up space on your internal hard drive. Otherwise, I recommend you install a bigger SD and mirror your existing one or rebuild your system. You can also continue to use the old memory by connecting it via an appropriate adapter. If you still have questions, just write again...