I maybe becoming a bit of a pest on these pages but as I have said previously I know nothing about computers and their workings, I have just had this message put on my screen.
Your Computer is Low On Memory
To restore enough memory for programs to work correctly save your files and then close or restart all open programs.
Now then I have not got a clue how to do this, would some kind person tell me how to go about doing this task.
Which bit don't you understand?
The easiest way to do this is just restart the computer
Click Start/Shutdown
Then, after it's powered down, just turn it back on again.
It sounds like you've got too many windows open at the same time. The simple solution is to close any that you are not using. Programs such as Word will ask if if you want to save the data others, such as AB won't. Then just open the programs you want.