Windows Explorer unwanted scrolling

I open Windows Explorer with the Windows keyboard key plus "e". I begin navigating in the left pane to the desired folder by using the scroll bars and expanding folders by using the + at the left of folder names. Not every time but most times the left panel will scroll of its own volition. Up or down, it does not seem to be consistent. Then I have to go back to the scroll bar and return the left pane to the view I wanted and was at. This happens on my laptop at work and my desktop at home. How do I configure Windows Explorer to stay where I put it?

Thanks.

Steve

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM)2 CPU 4400 @ 2.00GHz, Intel64 Family 6 Model 15 Stepping 2
Processor Count: 2
RAM: 2037 Mb
Graphics Card: Intel(R) G33/G31 Express Chipset Family, 256 Mb
Hard Drives: C: Total - 305195 MB, Free - 223191 MB;
Motherboard: Dell Inc., 0RY007
Antivirus: McAfee Anti-Virus and Anti-Spyware, Updated and Enabled