help changing sd card, makes phone freeze up

I have an lg optimus t from tmobile, it has android 2.2 froyo.
I bought a new micro sd card (a transcend 4gb class 6) to replace the 2gb it came with. I put the original sd card in my comp. and copied (not moved) the files to a temp folder. I put the new card in the comp and formatted it with the formatter on windows xp then (based on what I read) I formatted it again with the formatter downloaded from sd.org (both times full format, fat32), them copied the files to the card. When I put the card in the phone it kept freezing and I'd have to do a battery pull, and it didn't read any of my pics but you could look at the memory in settings and it showed the memory left on the card. I hit unmount and format on the phone then mount, then tried to transfer the files usb comp to phone. 1 by 1 several files went through fine then my comp said device not connected (i think), them the phone said sd card damaged, reformat. The phone wouldn't format it, and my computer won't format it either both format programs say card can't be formatted. I put my old card in phone and it works fine. Is the card ruined now? What did I do wrong? I'm getting another card, what is the procedure for changing cards? If I did it correctly why was my phone freezing bad? What should I try next time? I've never changed a card in any phone before so bear with me. Thank you

— modified on Sep 19, 2011, 2:25:14 PM by moderator

Sorry I typed it from my phone and it was hard to see the size.

I decided to just order a new card. I'm going to check on the warranty too. How do you suggest I change cards (from my orig 2gb that's still working fine to next new one)? Did I do it right the first time?

I've never changed a card or even put music or anything on my phone. I just assumed that was how to do it, I have no idea if I even did it the way you're supposed to.

— modified on Feb 5, 2011, 8:16:43 PM

Thank you, I tried it with an old 1gb card and it worked fine, no freezing and the phone could read it!
I don't know why I was under the impression I had to comp format it, particularly with the sdcard.com formatter to extend it's life or something?

There is so much bad info out there. I read somewhere I had to put it into recovery mode (i didn't know what that was) and change it that way. Needless to say I did it without backing my phone up, that's what I did before everything else that ruined the card.

Thank you again. My card should be here tomorrow, hopefully all goes well!!