I have purchased CS6 Indesign and cannot open CS4 Indesign files directly using Windows 7
What happens when you try? What is the file extension on the file you are trying to open? CS6 should open all .indd, .indt .inx and .idml files without a problem.
They are .indd file
Searching files and folders in windows 7 – all .indd files do not open directly
Are you using File > Open... or double-clicking in Explorer? What happens? Error messages?