Lexar 16g pro 133 sd card in canon ixus 750 says memory error card locked which ever way slide switch is. card is ok in computer Help

SD 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.

SD/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.

Could be faulty sd card and you may need to try another one to see if you get the same message.

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.

Look at the memory card. SD cards have a slide switch along one edge. The position farthest from the contacts locks the card, protecting it from writes. The position nearest the contacts unlocks the card. If the switch is already in the proper position, slide it fully the other way and then back again.

If that doesn't work, try another card.

The IXUS 50 works with SD cards. Your 4GB card is actually an SDHC card. While it fits into the slot, it is electronically incompatible and will not work. You need to use SD cards 2GB and smaller.

Did you try to format the cards before you tried to use them? Is the slide switch on the side of the card unlocked?

I assume that you know that there is a tiny tiny on-off switch on the edge of each SD card. If they are locked in the off position....

Remove the card and look for a tiny slide switch on the side of the card. Slide this switch to the other "unlocked" position. Reinsert the card and try it out.

It's most likely the locking switch on the edge of the memory card. Secure Digital cards have a locking mechanism on the side of the card to prevent accidental erasing of the data (that's the "secure" part of secure digital). Just slide the switch away from the locked position and try it in the camera again.