Adobe Flash Player has unfortunately become a liability for computer user in the last several years. The product facilitates displaying animations, sounds and videos on web pages, but has proven to be a very popular means to spread malware.
At the time of writing there is yet another "zero day" vulnerability going around. This is partly because Flash is so ubiquitous and therefore a tempting target to the bad guys.
Apart from trying to keep up with security patches for Adobe, one good way to reduce your exposure to malware possibly using Flash Player is to enable the "click to play" option in your web browser.
This simply means that Flash items will not automatically play (and potentially automatically infect your computer), but if you click on them you can allow them to play if you choose.
This is not hard to do, but the setting is different in the major browsers - see here for instructions for IE, Firefox, Safari and Chrome.