Can someone help with system variables?

I accidently edited my CLASSPATH and PATH under system variables and now my java isnt working... How do I edit these two so my java is working properly?

Reinstall Java is the easiest way. Goto java.com and click on Free Java Download.

Also, a System Restore to before you did the edit would fix this as well and is probably the better choice as there may be problems with more than Java.