Well, it was working OK yesterday but I plugged it into my laptop an hour ago and it doesn't light up and/or pop up on my screen to say that it has detected a new device. I have tried it on three other laptops and it doesn't work. I really need to know how to get it working again or to know how to retrieve the files which are saved on the memeory stick. Please help!

Have you tried blowing it out with canned air? Sometimes debris can get inside and caus you to lose connection. Make sure it is clean.