Printer - USB Device Drawing Too Much Power...

I have a Macbook Pro with Snow Leopard, and a HP Deskjet 2050. When i plug in my printer to the USB port in my mac, around 80% of the time the screenshot below appears, and I can't connect to my mac to print/scan.

It's really annoying me because it still works sometimes, but randomly, and once the message comes up, no matter how many times i unplug and plug in different wires it usually won't connect for the next few days.

I don't understand why the message keeps appearing, as the printer obviously can work perfectly well as it does every now and then, and i've tried it with and without something else plugged into the other USB port, as well as ensuring my laptop isn't doing much, and is fully charged.

I would be really grateful if anyone could help me.

Thanks!

Anyone have any idea?

Knoodles said:

Some questions more than answers.
What happens if the printer is powered on before connecting the USB cable?
How about if the power adapter is connected to the MBP?
Try a new USB cable?
Use a different USB port?
Some kind of intermittent power surge when connecting the printer?

Click to expand...

Tried plugging it in when it's off, when it's turning on, and when on and same thing comes up.
I've tried a new USB cable and the same thing happens.
Only have two USB ports, the front one the message doesn't show up when i plug it in sometimes but it still does not connect, whereas the back one it always shows up when plugged in.
Not sure about the power surge, but other things are plugged into the other sockets and they are all fine. I am at boarding school, and I am in a different room to last year in which the same problem occurred.