Windows Vista Vista downloads in ZIP

I have the Windows Vista Home Basic Ed. on my comp. For some reason windows almost always downloads files off the web in ZIP format. I have uploaded an MS PowerPoint Pres. onto the web as a normal PPT file, but when I try to open it from the web it wants to download as a compressed file. I have openned the same file from a different comp. using XP Pro and it downloads as a regular PPT file. Of course, this isn't the only problem I've had with it b/c it has done this with other files from the web that normally don't download as ZIP files. Is there a way to disable this feature? Any help would be appreciated. Thanks a bunch!

 

Hello bmoore and welcome to the Board

Check IE7's Add-ons: IE Tools > Manage Add-ons and go thru them. If you can't spot what it is, then disable them all > check to see whether it's the Add-on's, then re enable one by one.