word 2007 and 2003 coexisting on same machine

I am wondering if Office 2007 and 2003 can coexist? I have noticed that if
I open documents in Word 2007 and then go back and try to open something up
in Word 2003, the word 2003 is slow and the windows installer pops up and I
get the Preparing to Install message. After about a minute or so Word 03
opens up. People in my office would like to ability to open up their
documents in either program without the slow delay.

I noticed that you can make an registry change NoRereg to versions 11.0 and
12.0 in word which seems to have done the trick. I'm wondering if there
needs to be changes done to powerpoint, excel, access

What I would like to be able to do is when I click to open a document
created in word 2003 that word 2003 opens it and ones that are created in
2007, word 2007 opens. Is this possible. Right now 2007 wants to open
everything up