Harry,
Here is a post that I added three weeks ago. It includes a solution that worked for me. I hope that it works for you! Good luck.
Hey troubled Podheads,
I was one of the legion with problems in downloading iTunes6 and QT7 for Windows until I tried something (I must say that I am not a pc wizard and I don't know the technical reasons for why the following worked, it just did! So if there are any pc geeks out there, be sure to chime in). Anyway, this is what I did. First uninstall QuickTime if you do have it on your pc. If not, just go to the next step:
Go to START, then RUN. Type in regedit and then click OK. Your REGISTRY EDITOR should open. You should see HKEY
LOCALMACHINE in the scroll down menu on the left, with a small box to its left. Make sure that the inside of the box has a negative sign - this will open up the next set of subfolders. Next, make sure that the subfolder, SOFTWARE, has a negative sign in the small box to its left. Next, make sure that there is a negative sign in the box next to the subfolder entitled, Apple Computer, Inc. You'll see at least three subfolders: iPod, iTunes and QuickTime. Click once on the QuickTime folder until it is highlighted and then delete it. You will be asked if you want to delete QuickTime and its subfolders. Click ok and then close out the Registry Editor.
Next, download the stand alone QuickTime 7 at this link (you may have to cut and paste this link to open this website):
http://www.apple.com/quicktime/download/standalone.html
When you download the stand alone QT7, you may get a couple of error messages (I did), but if you repeatedly click ok (like I did), the QT7 player should load with no problems.
Again, I am no pc geek, but this worked for me and I have gained access to iTunes6 (with video capacity) and my complete library is intact. Nothing like trial and error!! Good luck -- I hope this works for all of you frustrated Podheads out there!