Because you mentioned that your SD card can be recognized by your PC, the loose connection and incompatible file system are ruled out. In my opinion, your SD card has gone RAW. As a result, I recommend that you retrieve data from the RAW SD card and then format it for normal use.
iBoysoft Data Recovery Software is highly recommended to recover data from an inaccessible SD card. It is designed with advanced disk scanning and recovery algorithms, helping you recover data from inaccessible, unreadable, formatted, corrupted, or failed SD cards, USB flash drives, pen drives, internal hard drives, and external hard drives.
With an intuitive user interface, it's easy to perform the RAW SD card recovery task:
Step 1: Free download iBoysoft Data Recovery and install it on your computer with a few clicks.
Step 2: Connect your SD card to your PC, launch this application, and choose the Data Recovery module in the main window of iBoysoft Data Recovery Software.
Step 3: Select your target drive and click "Next" to scan for lost data on this drive.
Step 4: Double-click to preview the scanning results, choose the recoverable files you need to recover, and click "Recover" to get them back.
With all data back, now you can format the SD card on Windows to make it functional:
Step 1: Right-click "My Computer" (or "This Computer") on the desktop, and click the Manage option.
Step 2: Choose Disk Management and select your SD card and right-click it.
Step 3: Select Format... and choose a file system on the pop-up Format window.
Step 4: Check Perform a quick format and click OK, and then wait for the SD card to be formatted.
Hope this answer can help you!