How to disable laptop keyboard temporarily in Windows 8.1?

Two days I've have had weird behavior on my laptop. This machine scrolls pages itself up randomly. And moves the cursor on the text to the beginning of the post. I have no idea why this is going on and it's bizarre 'cos I write this on notepad and gonna copy it to the forum and here it works fine. In forum I coud't write this 'cos cursor jumps every time to the beginning. Other strange this is when I click a folder on desktop it opens completely different folder and I do it again the right folder opens. This can't be only about keyboard lagging but I'd like to start there and see what happens. I obviously have external screen, mouse, keyboard. Thank you!!