I've bought 2 different Sd cards for my camera, and when I put them in, my camera locks up. It works fine without the Sd card.

put it in a computer and see what it reads,it might need formatting .

Actually, you didn't. You put in a new 4GB SDHC card. The camcorder works with SD cards, not with SDHC cards. You need to use SD cards, 2GB and smaller.

Put the SD memory card into an USB card reader and plug the card reader into the USB port of a working computer to check if the memory card is working.
If the computer cannot detect the memory card as an external storage device and cannot open the files or folders and it cannot be formatted in FAT32 then the SD memory card is faulty and needs to be replaced..

If you have the ability, put the card on something else and format it then try.

Make sure there's nothing in the slot, and you've got the card oriented properly. The i1237 works with SD and SDHC cards. The Transcend 2GB SD card should work fine.

According to the specs on Canon's web site, the IXUS 700 works with SD cards, not SDHC cards. SD cards are limited to 2GB in size (there are rare 4GB SD cards, but they tend not to work in SD devices).

Of course, it's your call as to how definitive any manufacturer's web site touting their product might be.

This error message means that the card is corrupted or formatted for another digital camera. Turn off the camera. Insert a new card or format the card.
Try to format the memmory card using a card reader and the PC this should solve your problem if not you have to replace the memmory card.

You may be restricted to using only SD cards, and many 4gb cards are actually SBHD. My sister had this problem with her camera and by putting in a new 2 gb SD card, her camera worked fine. You may need to shop online in order to find an SD card, but they're widely available online. It costs about the same for 2 2gb cards as one 4gb even though they aren't as convenient.

try to format them into your pc...maybe they are still raw and that why they do not work ...also ..read the manual and see what is the max value supported.. be sure they are formatted .in FAT ..system ..

The SD card has a lever on the side of it. Move it to the other position.That is to prevent accidental erasing.