when searching for slow opening word docs at microsoft it led me to this troubleshooting page http://support.microsoft.com/kb/921541
this was also interesting as it mentions google toolbar, similar situation as yours and more things to try. more kb articles linked to here also.
this guy blames Kodak EasyShare, do you have that program ?
do you have a network printer installed as default ? this from another forum.
Did you find a solution? I was having the same issue. I am on vacation connected to the wireless at the resort. If I disconnected, Word and Excel files open fine (both 2003 and 2007). Otherwise, they would take 10-15 minutes -- no matter how I access them (from Windows Explorer, form the program, etc.). Powerpoint was unaffected. I "disconnected" from my mapped network drives, deleted the "recently opened files" lists, etc., but the only thing I could do to open the files quickly was to disconnect from the wireless network here.
The solution was to set Adobe PDF as default printer -- because my default printer was a printer on my home network. Even though I was not trying to print, Excel and Word were apparently trying very hard to connect to to my network printer.