I bet a bunch of you know this already, but for those who don't, maybe I'll save you my frustration...
My stupid desktop icon size was driving me crazy. The default seems to be a tip of the hat to the 640x480 rez days. I was having a heck of a time finding where in control panel I could size them small enough to suit me, and finally googled for it.
A neat quick fix for the size is to left click on any icon, then hold down Ctrl and use your mouse wheel to size the icons to whatever you want.