Cursor jumps back when typing

The only thing that has worked for my Dell 1545 is to reinstall the software for the Touchpad, I've just done this now and it has completely resolved the problem (installing Touchfreeze and unchecking 'enhance pointer position' that have been mentioned elsewhere didn't do anything for mine). This is the second time I've had to do it, about three years after the first time, which is when I first bought the laptop. To install the correct driver:

Go to http://www.dell.com/support/drivers/us/en/04/DriversHome/NeedProductSelection

On right-hand side, click on ‘Search for drivers and download’.

Enter your service tag code - it's usually on a white panel on the back of your laptop.

From list it gives, choose ‘Input’ and then click to download the relevant driver for the Touchpad (the one for Dell 1545 is called ‘Alps driver’).

When you get the pop-up window, choose to save the file. Then open it and run it. Then restart the computer.

Problem should be solved!