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Internet Explorer starts multiple instances for the main frame window and multiple tabs inside it. EVen if you have only 1 tab open, you would have at least 2 iexplore.exe
running. This is normal.
If Internet Explorer makes your system slow, then possibly you have many browser add-ons (extensions) installed which load every time you load IE. Try running IE without any add-ons. Right-click on the IE icon on your desktop and choose Start without add-ons
. See if this makes any difference.