Memory Stick Pro Duo 4gb not detected.

Here's the situation. I have a memory stick (details mentioned in topic subject) that I use for my psp. It works normally in the psp. I have 2 laptops and a computer. 1 laptop uses Windows XP and it reads the memory stick, no problems. The computer used Windows Vista and when it reads the memory stick but says that there is a I/O error. The other laptop uses Windows 7 and the memory stick isn't detected at all. I'm not sure that the Windows 7 laptop is my fault, and that there is a faint chance i haven't inserted it properly but I have tried very hard. Up until now I've just used the Laptop that works but, that laptop crashed and died. Fixing the laptop aside are there any suggestions?
PLEASE HELP.

how are you connecting the ms to your computers via usb mode or an adapter? if its through an adapter it could be incompatible with windows vista/7

I just put the card into the slot which I assume is usb mode.

i should of been clearer, i meant usb mode from the psp via a mini usb (one of these http://www1.dealextreme.com/productimages/sku_65773_1.jpg) or an adapter like one of these http://www1.dealextreme.com/productimages/sku_0472_3.jpg

Like I said, I just insert the memory card into the slot meant for SD cards.

try updating you drivers if that doesnt help its possible that you sd slot is damaged

Don't worry about it. I bought a usb cable and it works. My sd slot wasn't damaged, I tried putting the camera's memory card in and it worked normally. Thanks anyway.