IE doesn't always fill new browser windows with a background before drawing the content, so if something causes displaying that content to hang, the symptom you describe can occur.
Are the OS installs on these from scratch or are you reconfiguring the default OEM install? If the later, is there anything similar to the following running?
[link|http://groups.google.com/groups?q=toshiba+laptop+ie+window+open&hl=en&lr=lang_en&ie=UTF-8&selm=3689e993.0309051151.2df853d5%40posting.google.com&rnum=2|http://groups.google...google.com&rnum=2]