I have a Advent laptop. I don' like using the laptop touch pad to control the mouse function so I got an external mouse. Since I first used the external mouse I find that I can only use the touch pad if I have switched on with the external mouse plugged in. (If I switch on without the external mouse connected I cannot use the touch pad at all, but when I connect the external mouse that works ok). How can I get the computer to recognise the internal mouse again?

Sorry for the delayed response.

What is the exact model of the Advent.

There might be a hotkey function or a need to reset the defaults in the BIOS.

UKT Support - Advent Index

Thanks for the response.
The computer is an Advent 7087

UKT Support - Advent 7087 Laptop

The above is the basic info on your model. Unfortunately I see nothing regarding the touchpad specifically.

When you first power on the computer do you see like "Press Delete to enter Setup" or perhaps press F2?

If so do so and enter the BIOS setup. Once here look for the option to load defaults > Save & Exit.