Micro SD suddenly read-only?? HELP!!

Hi, so I'm very new here, not very tech-savvy, and have run into a really frustrating problem. I have a (very old) R4 SDHC card, and I recently wanted to update it so I could play new games. Things were going pretty bad, I downloaded Wood v1.26, but got stuck on the loading screen, but then I stuck the USB back in and suddenly all the files were read only. I needed to delete some of them to try to update the card, but I can't. I'm running Mac OS X 10.6.6, and when I heard about the NTFS thing etc., but it doesn't make sense to me because THE FILES WEREN'T READ-ONLY BEFORE. I don't know what I did, but I could delete them fine the first time, and then suddenly couldn't do anything, not even adding more files to the Micro SD card...If anyone knows what's going on, please help!! Now the card is stuck on v1.26, so I can't do anything with it.

you can do one of the following.1. find out how to get administrative rights on the computer and completelly format the micro sd.
2. go onto the micro sd properties and change the rights to read and write

Did you use an adapter to access the microSD....you know, like a full size SD adapter to put the microSD into so you could access it in a reader? If you did, you may have accidentally flicked the little switch on the adapter to "lock" which will make the files on the microSD read-only.To fix it, put the microSD back into the adapter and make sure the switch is NOT set to "lock". That SHOULD fix it and allow you to remove or change files.Hope that helps you.