If there isn't a tiny switch on the memorey card or stick, try this Registry fix.
Press your Windows key and R together and in the Open box, type regedit then press Enter. From the File menu, choose Export then note the name and location of the backup you are about to create - it may save your system later.
Then, navigate in the same way you would in Windows Explorer, to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control \StorageDevicePolicies.
Double click to open Write Protected File and and change the value to " 0 " then click ok.