The laptop is a Toshiba Satellite
The programme I'm using (Media Player Classic) requires access to the Number keypad (as on a PC) to make changes to the image size. These are the 2,4,6, and 8 keys which I believe have the alternate assignments on the laptop For example Key 8 on the laptop has two other assignments - an up arrow on the left of the key (accessed by the Function key + Key 8) or an 8 if the Function + Alt + key 8 are pressed) For MPC, Key 8 from the number keypad increases decreases the width of the image. Alternatively laptop Key K has the alternative assignment of 2 on a PC accessed by pressing Functn + Alt + K.
Using these assignments with MPC produces a different result. The four keys above instead of modifying the image, turn it through 180 degrees i.e. pressing Function + Alt + K (2), inverts the image. Similarly the equivalents of 4 and 5 tunr the moving image on its side

Not very useful.
Any clues out there? Incidentally the same version of MPC runs perfectly on my PC - both computers run Windows XP.
Ross