Hmmmm..... curiouser and curiouser...
A couple of things:
1. You said your HD is 69% full, but not how big it is. Do you have enough free space?
2. You can free up some free space by tweaking IE settings. One of the standard settings, browser cache in IE, decides how much hard drive space to reserve for your browser's cache -- copies of things you've looked at. The default is 10%, which is astronomical. I get by quite happily at 1-2%, which makes about 100MB on this machine. Tweak it down, and then clear your history in IE. You may be amazed at how much space comes back.
3. Is LotR designed for XP? You can check the Tech Tips thread on the
W&W forum for suggestions on making W&W work under XP. Some of those tips may apply to you, especially the "win 98 compatibility" one. 'Course, they may not apply until you can finally load it...
Let us know...