Keyboard?

[crapmemory]

As I type the cursor disappears and letters do not appear.It's so annoying, it takes me AGES to type anything! Any suggestions (keep it simple please).TIA

[Buenchico]

Which device? A Windows PC? An Apple Mac? An Ipad? An Android device?

Does it only happen when typing into your web browser or also when typing, say, a Word document?

[Jennykenny]

Check out the 'insert' and 'delete' keys. Just press one or the other and see if it makes a difference.
You may be overwriting.

[Cloverjo]

Is it on an iPad? If so, it helps for a little while to reset the keyboard dictionary. Go to Settings > General >Reset > reset keyboard dictionary

[mikey4444]

Are you using a wifi keyboard ? I get that trouble when the batteries start to run down.

If you are using that kind of keyboard, try swapping it for a wired keyboard, and see what happens.

[crapmemory]

Sorry I didn't give enough information. It's a Toshiba laptop using windows 7. It happens on everything I try to type on, i.e. on AB, emails, forms etc.

[Buenchico]

Something is hogging all of your laptop's resources. The most common cause is a fault with the updating element of your security software. (Microsoft Security Essentials and Windows Defender are particularly prone to the problem but AVG, Norton and others have all been known to have suffered from it). So try uninstalling your security software, restarting your laptop and then reinstalling it (or installing something different).

Another cause of resource-hogging can be the presence of malware. Run a scan with the free version of Malwarebytes to look for anything nasty on your computer:
https://www.malwarebytes.com/antimalware/

[Old_Geezer]

Does cycling the power help any ?

[crapmemory]

I have tried all your suggestions(apart from the one from OG because I don't know what that means!). Sadly, no difference at all :(