PC won't recognise keyboard or mouse

[Tailchaser]

Hello,
I moved my PC (Dell, 2006 vintage), the first time since I bought it, disconnecting and reconnecting all the peripherals. Now, when I turn it on, Windows XP opens and the desktop appears on the monitor as normal, but neither the keyboard nor the mouse will work. Nothing happens if I try to plug them into a USB port, yet if I plug in a memory stick, for example, Windows recognises that as a new piece of hardware. Any suggestions as to what is wrong will be gratefully received.

 

[alvine]

try removing the connects and plugging them back in while in windows

 

[Tailchaser]

Thank you very much for the suggestion. I tried it but nothing happened. As before, I can plug in a USB stick and that's recognised, but the keyboard and mouse aren't - but there doesn't seem to be anything wrong with them as they work OK in my netbook.

 

[Tailchaser]

I've been trying various things. If I switch on the PC and the keyboard isn't plugged in, "Keyboard failure" appears on the screen before Windows starts to load. If I then plug the keyboard or the mouse into one of the back ports I get a message along the lines of "your new hardware device may not have been installed properly". Is this serious? (It's no doubt clear already that I'm not expert in computer matters.)

 

[Tailchaser]

Moreover, it transpires that the keyboard works during booting - for example CTRL-I or F1 - but stops working when Windows is loaded. I'm no closer to a solution. Can anyone tell me what's wrong, please?