I need to sign in to my Google Account but can't as no link available so can't use tablet I haven't used my tablet for a while &amp; in that time I've changed my google account  password. 
I can only think that this is why it won't let me access anything but when it tells me that I need to sign in to my Google account I don't know how to do it. Feel a bit of an idiot!!
It's very simple (its fine, everyone is a bit of an idiot). All you have to do is go to the gmail app. Then reload your mail. It will tell you that your sign in details are out of date. Click on change (or a similar option) and you're done!