Check your file extension association

Hi, I install and uninstall so many freeware application in my Windows XP almost everyday and I often be confused about its impact. And I get error everywhere in my Windows. So I must fix all messes in there. And one of "messes" is my file association be destroyed too.
And first step that I take is checking file association now, where it be linked. For example, usually my .doc file was association to Microsoft Word but maybe after I install OpenOffice and uninstalled it but .doc file still refer to OpenOffice application.
You can check it via Tools - Option menu on Windows Explorer. But I am more like to check it via command prompt console (MSDOS) command. OK we will try it.
First, open Command Prompt Console, you can do it via Start - Run menu and then type cmd in textbox or via Start - All Programs - Accessories - Command Prompt menu.
Then use assoc command to check it. Just type assoc at prompt to display all file associations.
Or if you want to check certain file extension type assoc ., for example assoc .doc then your .doc file association will displayed as its result.