I've tried powering it both from USB and plugging it into a wall and windows still doesnt see anything

any other USB component I plug into the same port is recognised straight away, just not this

It may be you have a defective unit. I am sorry about that.

It's ok haha

I'd just like to thank you all for your help and quick replies, nice to know theres someone there to offer solutions if I hit another brick wall again!!

I think I'll just return it and get another one, see how I get on from there :)

thanks again!!

With your good nature I wish you the best. The course you will take is the right one. Besides it will be just that much newer.

I don't know if this applies to the M-Audio Keystation or not, but for my Evolution MK-249C USB midi keyboard which is also class compliant and does not require driver installation for XP, in device manager it shows up under Sound, video game controllers and is named USB Audio Device. By leaving Device Manager open, I can see the devices refresh when pluging in the usb cable, and it pops up under Sound, video game controllers.

Again, I'm not sure if the M-Audio Keystation works any differently as far as being recorgnized by Windows in Device Manager, but I thought I'd mention it since where my MK-249C shows up in Device Manager and the generic name it uses can be easily missed.

ORIGINAL: John
 
It matters where you get power to run it. If you are getting it from the USB port you may need to goto the properties of that port in device manger and be sure the power is always on. Ideally use a wall wart to power it and save the power drain from your PC. XP or Vista should alert you when you power it on if it is installed correctly.
 

 
Actually, M-Audio advises against using the wall wart IF the keyboard is going to be connected via USB cable instead of MIDI cable. The OP stated that the "blue LED" (power indicators) are coming on so his USB ports are providing power. He's tried two different computers with no success. I'm guessing the keyboard is defective and just isn't sending MIDI info via the USB cable.
 
My only other guess is that the OP has a serious IRQ conflict with USB porting that's preventing his OS system from actually recognizing the Keystation but still sending power to it. I've heard of this happening with M-Audio USB devices conflicting with such things as USB ported webcams and/or video capture devices.
 
Still, the fact that his keyboard isn't working on both computers bothers me. I have an M-Audio Keystation 88. USB connected to my computer and the MIDI cable output connected to additional keyboard synths which are MIDI connected to my M-Audio AP192's MIDI I/O's and the external synth audio outs connected to my mixer which feeds the M-Audio AP192 soundcard.
 
Forgive the rambling, I'm just trying to help the OP get his situation straightened out.

Actually, M-Audio advises against using the wall wart IF the keyboard is going to be connected via USB cable instead of MIDI cable. The OP stated that the "blue LED" (power indicators) are coming on so his USB ports are providing power. He's tried two different computers with no success. I'm guessing the keyboard is defective and just isn't sending MIDI info via the USB cable.

Extremely good points and I am glad you posted them. I avoid using USB with so many devices. I have a MIDI port that is USB. All my gear goes to it. Thats why I think about wall warts. LOL

Is it an older Keystation, (black not silver)that says "Midiman"? (not M-Audio)

The reason I ask is I had an one of the older 61 key units and I could not get it working on my XP system.  I also lent it to a friend with a MAC who could not get it working.   I think the older units have some driver issue that makes it difficult to install.  MAudios website suggested using the drivers for their newer keyboards - but that didn't work either.  I ended up giving the unit to a friend who uses it as a midi devise controller with the wall wart.

WDI: I looked again through my device manager and it doesnt mention anything about a USB device anywhere when its plugged in. Thanks though!

NW Smith: It's a silver one that doesnt like me

so this is an ancient post - but i had a similar problem with my keystation 49es not showing up in SONAR (Windows 7 64bit). after re-installing the driver and turning my computer on and off, i found that the issue was that i changed the cable to a longer cable that came with my printer. when i went back to the original cable that came with the keyboard it showed up fine. apparently it does not like longer cables or there's something specific to the OEM cable.