How can I convertmy Motorola Surfboard SB5100 Cable Modem to wireless

what do I need to buy ?

Would this work ?

http://www.amazon.co.uk/Wireless-I [...] 471&sr=1-1

also, on the back of the modem is a rectangular, not the typical, usb slot, if that helps.
look

okay. so what do I do ?

EDIT : I want to move my computer downstairs.

I cannot move the modem because it is connected to the wall.
I don't want to use an extra long wire either.

What do I need to buy so I can use the wired modem,

as a wireless one on my pc downstairs ?

That's only for a computer. The USB slot is a regular USB, it's just the other side of the cable used for devices not PC connections.

You need a Wireless Router. Take a look at this http://www.amazon.co.uk/TP-Link-TL [...] omputers_2

There are cheaper ones, but you want one that will work across floors. The one I linked has good reviews for it's signal strength. One that's worse may still work, but maybe slower, have drop outs, etc...

Not that it's guaranteed that the one I linked will work for you, it really depends on the distance between the PC and the Router and what's in between them.

Yes, setup Router, note the wifi settings and password you select, install the USB wifi in the computer, it will come up with a list of wireless networks it sees. Pick yours, enter password, done.

hang-the-9 is right, a wireless N router and copatible adaptor on your pc will give you better range than a wireless G router. Without any garantees it's probably the best solution.