I don't where to even post this question.
Setup: Dell 4550 2.4Ghz unit 10 months old. Windows XP Home Logitech optical cordless Mouse.
Problem: In the last couple of days I noticed the problem. Don't know how long it was actually happening. No new software or hardware installed.
What happens in "Most" (but not all) websites or on the Preview pane of Outlook Express or Word Documents (Excel documents are fine!):
I click on the scroll bar below the button (to accomplish a page-down action) the page moves TWO pages down. I can confirm this by clicking the "Page-up" portion of the scrollbar - which seems to work fine - or by using the keyboard page-down and page-up keys.
I have tried a complete cold resting boot and the problem remains. Tried virus scans and spyware scans - nothing. I have Tweak UI XP installed and there is no setting for how much a scrollbar click moves pages down or up. And, this happens on most but not all websites and Up works fine - just down is DOUBLED UP. It even happened in the post box that I created this question in.