Hi folks, sorry about the lack of replies.
The easiest way to see to try and fix this is to download IE7 again and choose to Repair the Installation. (not sure on the wording of all that as I do not use IE, but I remember seeing it there.)
Download details: Windows Internet Explorer 7 for Windows XP SP2
The other option you have is to just quit using IE all together and start using Mozilla Firefox.
Mozilla - Home of the Firefox web browser and Thunderbird email client
It is much more reliable than IE is.