why can i only some programs and files and not all by double clicking in windows 7 32 bit
I am going to guess that your question is "Why can I only open some files by double-clicking on them in Explorer in Windows 7 32-bit?
". If that's the question, then the answer lies in an idea called File Associations. Some file types/file extensions have an application associated with them, and double-clicking a file of that type opens it in that application.
For example: if you have a file called WhatIDidOnMyHolidays.doc, and you have Microsoft Office installed, then the file extension (type) "doc" is usually associated with Word, so double-clicking that file name will open Word and load that document.
Not every file extension is associated with an application. If you saved a document as "MyHolidays.XYZ", then double-clicking the file would not open it in Word, because XYZ is not associated with an application. You can add the extension to the list and associate it with Word if you want, but it's easier and more logical just to save the document as "MyHolidays.doc".
This used to be easy to understand until some genius thought it would be clever to hide filename extensions...