The keyboard has stopped working on the computer (windows 7 prof) tried changing it but no power to it, it's not a USB one its the ones with the purple round plug,any help will be appreciated.
PS2 (that's the one with the round plug) keyboards are only recognised if they are connected at the time of power up. So if you try another keyboard, you must shut down, swap the keyboards and restart. If you just swapped it out while the computer was running, that would explain why the second one didn't work either.
From past experience I've found PS2 can blow fairly easily. A number of my past PCs continued with the keyboard plugged into a USB adapter after the PS2 failed.