northumbria61 Thanks for that. I had already cleaned the four pads and have just tried to access the internals as you suggest and removed the screw, but the top does not seem to want to separate from the lower. It is very, very tight almost as if there was something else holding it back.

Woolwell.

Had also tried on different surfaces but no different.

northumbria61 Yes I had tried mouse settings previously, but just thought that I would look at it again after you suggested it ..................It must have had something to do with the broadcasting of the Olympic Games... the settings for the mouse had gone back to slow.... Set them to fast... All hunky dory now.
Olympic Games --- I have to blame something at my age, it was not me!!!

Two years ago, I purchased a Microsoft Wireless keyboard 800 and mouse package. I look at my keyboard NOW and the keyboard is the keyboard 800 and the mouse is the Mouse 1000...????

Northumbria There is no Wireless connect button underneath???

Both the keyboard and the mouse use the same receiver. I have moved the receiver to another USB port, this makes no difference to the jerkiness of the mouse. I have used a Logitech wireless mouse in both the original USB port used by the Mouse 1000 and everything is working fine. A wired mouse works fine. The same Logitech mouse is used in other USB ports and all works OK. So it comes down to the Mouse 1000 itself - I have cleaned the four pads on the underside, have blown out the internals, have wiped the optical part and am now considering the purchase of another complete Wireless Keyboard and mouse, but I do not like being beaten. I realise that I could carry on with the keyboard and also the Logitech mouse but that takes up two USB ports.

Any thoughts as to what else I can do?