Counting file sizes and lenghts together

Hi, I have couple questions for you... Be gentle, I'm a beginner :)

1. If I know a file's size in bytes, how can I convert it to decimal that shows it in megabytes with 3 or more digits? As in, 0,00 MB?

2. How can I count many files together in format like 0,00 MB?

3. If I know an mp3 file's lenght in seconds and milliseconds (stored in System.Time variable), how can I display it like 00:00:00 (hh:mm:ss)?

5. How can I count file lenghts together like using format 00:00:00?

1 KB = 1024 B
1 MB = 1024 KB

and so on ... bt I'm sure you know how to divide and format numbers.

This may help

Thank you both for your answers. Now, if only someone could help me with formatting System.Time... ;)

The play time of your mp3 file is a duration of time, so you would use the TimeSpan class. Once you get the play time as a timespan object, you can do calculations and call its ToString method to display it.

Thank you stanav for your answer, it didn't quite explain it to me but I was on the right track by your answer. Actually, this is what I was after:

Format (System.TimeSpan.Hours.ToString, "00")

(In case someone else needs to know this stuff...)