I ran across an issue today that Vista made a bit difficult to get around. It appears that Microsoft removed the option to turn on/off the "Browse in same window" option in Vista for file type associations. In prior versions, to make Internet Explorer show a word or excel document in the browswer instead of opening a new window, one could simply go to Tools..Folder Options, click on the File Types tab, find the file type you wanted to alter and click the Advanced Tab. There was then a check box to allow browsing in the same window or to force office to open the document outside of the browser.

In Vista, file types are altered via Default Programs in the Control Panel, option titled "Associate a file type or protocol with a program". Unfortunately, the advanced options available in prior versions of windows are no longer there. To get around this, the only way I have found thus far is to use regedit and make the following changes for Excel:

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Excel.Sheet.8]
"BrowserFlags"=0

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Excel.Sheet.12]
"BrowserFlags"=0

To force new windows instead of keeping it in the same window, use 8 instead of 0.

Microsoft has a knowledge base article on this that details the keys for other Office documents as well at:

www.mssoftwareconsulting.com/general/Refer.aspx?url=http://support.microsoft.com/?scid=kb;en-us;162059