Ok then, the problem seems to be solved now, and I'm back where I should be.
The problem was...………………………..the wireless keyboard and mouse.
I use this in conjunction with my laptop as I don't like the laptop keyboard or the finger pad thingy.
Just before my problems occurred, I was tapping out an e mail and the keyboard was playing up e.g. I'd tap out a c but a 6 would appear and a space would appear in the middle of a word etc etc. I changed the two AAA batteries in the keyboard and the mouse but the problem still occurred.
Using the laptop keyboard has now solved the problem until I can get a replacement external one. Thanks again for all the advice.