Well I un-installed IE8 via the installed update, via Control Panel -> Programs & features -> view installed updates and uninstalled update for IE8. IE7 was then restored and her version is 7.0.6001.18005.
Then went into Internet Options and changed all settings under Security & Advanced to the same as mine.
On hers however, we still have the problem of not being able to install the root certifificate.
Now the only obvious difference between hers and mine is User Account Control (UAC). It's found under Control Panel -> Windows Security Centre -> Other Security Settings -> User Account Control. Mine is unclicked and hers is clicked on. Wonder is this the problem? The reason I ask is I unclicked mine ages ago and while she doesn't mind the box popping up (while I did) I've a feeling this might be the difference, then again maybe not.
Any suggestions?? For those with IE7/IE8 and Vista and able to install root certificates do ye have the UAC clicked on or not?
As an aside, we use our own antivirus and firewall (Kaspersky IS7 so Windows Firewall is disabled) but don't have problems.
We're leaving IE7 on hers - at least for the moment. She much prefers it's functionality and usablity compared to IE8 which she really didn't like.
Re Firefox. Yeah we could, but it doesn't allow other things which I'm aware of so and I know a good few users of it seem to have to have both IE and Firefox installed and use them for different types of sites, so once I get this sorted, she'll be happy.
Might be a week now before I get my hands on her laptop again.