this is very basic it usually means you don't have a flash player. or it could be a virus, spyware, or adware. a third possiblity it could be blocked

do the following scans, anti-virus, anti-spyware, anti-adware,
get macromedia flash player
avoid flash pages

please report back and tell me how it goes here are a few
programs that i recommend if you don't have the software needed to do the scan

name purpose
AVG anti-virus
spybotS&D anti-spyware
ad-awareSE anti-adware

to find them search for them using a search engine