Desktop refresh/ rearrange icons

okay not sure whats doing it looked all over web still nothing. here is my
prob when ever i try to open my documents, my computer, control panel or
other folders and such my icons on my desktop will rearrange themselves out
of the order i had them in sometimes. this also happens sometimes when i turn
my computer on or when i restart it. when the desktop loads it will refresh
like 3-5 times i think and as it is refreshing they will be moving around and
after the refreshing is done the icons will sometimes be they way i left them
other times i have to arrange them again.

im running windows xp pro sp3