macromedia flash player. What is this, & is it safe?

Just under the toolbar a blue bar keeps popping up and asking me to download the micromedia flashplayer. I'm not too sure what it is and I dont want to create problems with my computer. I had a problem with a serch engine called lop.com on my other computer & it was horrific. It slowed everything down to a snails pace & drove me mad with pop ups. It's toolbar followed me around to whatever site I was on and would change the titles on the it's toolbar to whatever subject I was looking at at the time. it nearly dove me nuts. Question is, do I dlownload micromedia flash player or not?