Are you using a laptop? If so, you need to be very careful about where you set your palms/wrists down, because it's all too easy to accidentally rest them on the trackpad, which interprets it as a mouse press. And on some keyboards, it can be easy to accidentally hit an arrow key or something when you thought you were hitting some OTHER key.
I use windows vista home premium SP2,windows explorer 8,all the
windows updates are entered. The problem is when I type text for
E mails or even this message all the text suddenly turns blue &
disapears & I have to type the whole text again.