hello, firefox may blocklist old plugin versions that are known to be vulnerable & actively exploited on the web in order to protect users - so please keep your plugins up-to-date! (i don't get the second part of your question?!)

no i been using a site for 2 yrs.now i cant because of firefox plugin containers update.cant even use chrome cause firefox infected chrome too

Firefox does not touch Chrome in any fashion. You can even run it off a flash drive for example.

Your Flash plugin may be older and therefore vulnerable as to why Firefox has in blocked version you have from being used in Firefox like for example Adobe Flash 10.2.* and lower has been blocked for your protection

According to More system details link on right of your post, you have the old Shockwave Flash 11.1 r102

then how am i spose to upgrade it when firefox wont let me.and i tried it on chrome i get msg firefox plugin container is preveting this download