White out of IE 8 only on windows 7, only certain important site

Can anyone shed any light on this.
Users of Windows 7 with IE8 suffer from a hanging system when visiting a certain site. IE goes white and many times hangs the system, so only holding the power button and shutting down will rectify the situation.
Now, the more serious problem is that the only site this affects is the childrens software program. Parenta. Therefore, a resolution is seriously needed, as this software is crucial to the running and the safety of the children at nurseries.
It only seems to affect Win 7 and IE. Parenta have only written the software for IE, nothing else will work.
I've got some of the nurseries using Opera to create reports; it works for that.
To say I am beyond reluctant to install Win XP on all these machines is an understatement!
Any ideas how to stop this major grief to the teams at the nurseries?
The site uses https and the info is being pulled from SQL; so might point to a timing issue.
The site is added to trusted sites. I don't know where to turn. I've tried disabling any add ons, but there were very few there any way.
Help!!! Picture hair pulling.
Cheers
John