Unable to access compiled file

Hai Friends,
I have a collection of java files. i stored them in a different folder(in different drive-d

than the actual java jdk pack folder(in c

.
I can able to compile separate java files in d: and the compiled class files are stored in d only.
My problem is if i am using 2 java files and one is referring another one:
When i compile the first java file which has no reference of the another one-get compiled corrected and the class file is created on the d: drive directory.
But when i compile the second java file which has reference of the first java -I am getting error message as the first java file - class not found error even it is compiled and there is the compiled class. Even both are in the same directory.

Plz help me.
Thank you.

Thanks to:
Ernest Friedman-Hill
I set the class path with current and the java directory as mentioned by "Ernest Friedman-Hill " in another post.
Ernest Friedman-Hill >>in that post:
If you've set CLASSPATH to something, mnake sure it includes a dot (.) to represent the current directory; i.e.,
.;whatever;something-else
and it works.
Thank you again Ernest Friedman-Hill