Canon IXUS 960is - came to use this morning and "Card Locked". Cannot find how to unlock? Can you advise?

Look at your memory card. SD and SDHC cards have a slide switch along one edge. The position farthest from the metal contacts locks the card, protecting it from writes. The position nearest the contacts unlocks the card.

how do I fix "MEMORY CARD ERROR"

Yes. The IXUS 60 was designed to work with SD cards. Cards larger than 2GB are actually SDHC (the HC stands for High Capacity) and will not work in this camera.

.....Open your memory card........Adapter And see There IZZ a ThiNg named Lockand UNLOCk That!!!! i guEsS that woULd Work.....

Move the slide switch on the side of the card.

Remove the SD card from the camera. Slide the tiny switch on the side of the card to its other "unlocked" position. Reinsert the card in the camera.

But if you have already tried this, see this link for additional things that you can try.

There is a little slide switch on the side of the SD card that will lock it.  It could be that it got bumped the last time it was inserted, or the memory card could be defective.  I saw this happen with a SanDisk card that hadn't been removed from the camera.  Removing the card and sliding the lock switch back and forth, then re-inserting finally solved the problem.  It was a bit disconcerting when it happened.  I would recommend that you get a replacement memory card to use if it starts to happen repeatedly.

turn on your camera.
look at the screen on the back.
press the "DISP" button until you see a picture with writing and information,in right hand corner of the screen there is a battery icon along with others , if its full so is the battery

Take the card out. On the left side of the card is a tiny white switch. Reverse the position.

On your memory card there is a little switch on the side click it the oppisite way you have it and it should unlock the memory card

lock and unlock you want to unlock it