so this is what i did. i created a folder called java to store my programs. i did the "hello world" program and saved it as hello.java. i went to dos and typed in C:\>cd java and it said invalid directory. then i put the program in the bin folder and did C:\>cd j2sdk1.4.1_02\bin and it said invalid directory. then i did C:\>cd java \bin and so on and still got the same invalid directory. should i put C:\>cd java\hello or C:\>cd j2sdk1.4.1_02\bin\hello to do that?