Problem with Java Pug ins???

Everyso often when I try to pull something up or like today when I tried to get into yahoo games this message popped up.... Java(Tm) plug in fatal error.......... What does that mean and how do I fix it!! Whit out messing up my computer!! ALso just so you know Under Programs it says I have the following java related programs.. Java (Tm) SE runtime enviroment 6 update 1..........J2SE runtime enviroment 5.0 update10 and ....J2SE runtime enviroment 5.0 update 11........... I am not sure if that info is neede to help me with this but I thought it might!! I am not that good with computers so please make the answer/directions detailed and easy to follow thanks in advance!!!