i have several computers with xp installed. on some of them, the file/directory/whatever is selected when the mouse goes over the icon. That is, items are automatically selected with simply putting the cursor on it; highlighting is performed without any clicks.
On my other computer you actually have to click the file to highlight and then click it once more to open the file.
I've looked on my mouse settings to see if i can change this but I cant find it anywhere.