Just recently, every time I start Internet Explorer, a windows installer window pops up which says "preparing to install", and it also has a cancel button at the bottom right corner. Why is this coming up every time I start IE. It takes about 3 minutes until the window goes away. Any feedback would be greatly appreciated. Thanks.

Run Adaware and Spybot (do a definition-update first).
You may have been hijacked.

Tried that, it doesnt remove it.

Did you run spybot etc in safe mode ? if you didn't you are not going to get rid of it, hijacks will rename themselves and other such things to stop from being deleted if you run in safe mode there is less chance of it being able to do that, also if you are using XP it may have infected your System restore this doesn't get scanned by Adaware etc and will not be removed from it so it's best to disable it.

perhaps u can remove IE and install it again?

Are you running Microsoft Office and have the Office Shortcut Bar open? If so, close it once, run IE again, let it install and re-open the bar. I've seen this "numerous" times here in a corporate setting. Some files that the bar uses prevents the load from finishing.

I was looking for a solution for the exact same problem when I found this thread. I have managed to resolve the problem though. Here's how my trouble started and finished.

A system was brought to me with "problems" and I was given little detail. I found that when Internet Explorer or any Office application was opened, the Windows Installer started. At first, I had to put the XP OS CD in to get IE or the Office app to finish opening. I did find out that the user of my system had uninstalled Office XP Standard and installed Office XP Pro and that's when this issue started. I reinstalled Office XP Pro and the trouble went away. I think the installer somehow got "stuck" and when I did the reinstall, what ever file that was currupted, got fixed.

I hope you can take from what I did to help you resolve your problem.

Matt

im getting this exact same error but im totally computer illeterate so i need more explanation of how to fix it ?
thanks
lance