Problem with new camcorder and computer  

I'm not sure if this goes here, but I need some quick advice! My sister in law got a new JVC camcorder for Christmas. She took some nice videos and wants to put them onto Facebook. She had both of her children try to help her, and even a friend or two, but can't figure it out. So she asked me if I could possibly help. I'm not sure if I can but here's what's going on:

When we insert the sdhc card into her computer, the files will copy over to the computer. But we can't view them. The format [or type] is MOD, and every program we try to view them with says it can't, mostly because there was an 'error' or they don't support that file type. Her's is an odd computer, E machine, but she has the windows program on it. We tried every program she had on her computer, and nothing. I thought maybe we had to change the format [?] to be able to view them. I personally don't know how you would do that though, because my camera sd memory card works just fine. We also tried plugging it in using the USB port, and still nothing. So I took the card home with me to see if I could figure it out on my own laptop, a Dell Studio. But this morning when I tried to put the card it, it wouldn't even recognize it; I can't get my computer to recognize the card. I've never had a problem before because I've put in other people's memory cards and it works just fine. But it kept telling me to insert the card, while it was already in. My memory card was in this morning, and working. I took it out to put hers in the computer, and it wouldn't recognize it. But when I took it out and tried to put mine back in it wouldn't recognize mine either!

So there's a couple problems: What can I do to be able to view her files? Why after putting hers in and taking it out won't my computer recognize that my memory card is in, when I've never had a problem before?

So I'm going back to her house this afternoon, and I was wondering if anyone could help me out? Do you know what could be going on and if there's anything I can do?