1) On the right of the screen there are two arrows at the top and bottom for scrolling up or down. A toolbar at the bottom of the screen covers the bottom arrow making it difficult for scrolling up an down. How can I get rid of this tool bar? 2) Looking to buy a second hand laptop - how can I make sure there's nothing dodgy on the hard drive? Thanks
1). Is it the toolbar with the start button in the corner? - if so, right-click on it and select properties then "Keep Taskbar on top of other windows" 2). Easiest way is to reinstall Windows and select to format the drive during installation. You will lose any software on it though. The other option is to install and run a decent free AV (AVG/Avast) and malware scanner (MalwareBytes).
If you can still access a computer then google the virus - few ways to remove it or as scoff said install some of the above programs - they should shift it