Keyboard not working

I've been using a Logitech wireless keyboard & mouse for ages but this week the keyboard stopped working. I tried all the usual things, replaced the batteries, tried reconnecting, updated drivers, tried a different USB port for the wireless connector & rebooted many times but nothing helped. I concluded that the keyboard had died & bought another one, a Technika. I un-installed the Logitech drivers & installed the new mouse & keyboard (plug & play, no drivers required) but the result is the same, the mouse works OK but the keyboard will not work at all. The device manager says that it is working properly, I've now got a PS2 keyboard plugged in & that works OK.

I really don't know where else to look for whatever the problem is, can anyone suggest what I should do?

PC is local built AMD Athlon II X2 245 2.9GHz
3Gb RAM
WinXP Pro SP2

 

I though I would try my old & new mouse/keyboard units in another computer. I tried the original Logitech mouse & keyboard & the result was the same as with my desktop, no keyboard. The replacement Technika unit worked perfectly on my laptop so I then plugged the receiver back into my desktop & re-connected mouse and keyboard;- they both now work.

I have no idea what the problem was or why it is now fixed but I have a working wireless keyboard again.:confused