Q. How can I get rid of pop-up advertisements?

A. To stop advertisements opening in new windows you need a pop-up blocker. Both Internet Explorer and Firefox have built-in pop-up blockers. In IE go to Tools, then Pop-up blocker to turn it on or change your settings. In Firefox, go to Tools then Options, then Content, and put a tick next to Block pop-up windows.

Q. My new computer keeps showing a pop-up advertisement trying to persuade me to buy something called DataSafe Backup. I've checked the box for no further reminders, but that hasn't stopped it. Is there any way to stop these annoying pop-ups?

A. This is not a virus, but something known as "nagware". (It should therefore have stopped when you told it to!) Whilst this particular product is a service from Dell - it is a "Cloud computing" offering providing online storage - nagware comes from many sources. PC manufacturers are paid by developers of software to install it, and are often paid a commission if people are persuaded by it. Their justification is that it enables them to keep the price of hardware down. You can delete it by finding it in the Programs and Features (Add/Remove Programs in older operating systems) in the Windows Control Panel, and clicking on the uninstall option next to it. By-the-by, if you are interested in using online storage, one of the best offerings is Dropbox, which gives you 2GB of space free.