Wierd things have been happening on my system; WInk 2K (service pack 3), Dell Dimention 450 with pentium 3, Voodoo3 (3dfx Interactve) display adapter, and a MultiSync LCD 1530 flat panel display.
1) Frequently, a page will get "screwed up"; some of the info on the page will just go away, but come back by just postioning the mouse over the area (a very quick hover) or by refreshing the page. Sometimes refreshing the page doesn't correct it. Frequently trying to open a menu in the start menu with a right arrow will not show the new menu to the side until you slide the mouse pointer down the new menu list, and as you do, eith choice will appear. Until then, all you see is the normal background. This often occurs with right clicking something-- the menu won't appear until you scroll the mouse over it.
2) WHen i open a window (such as "run") that has a fill in box, with a downward arrow to the right of the back, which if clicked on would give a menu of choices, the right box has a "6" in it instead of the arrow.
3) Icons frequently get lost: the desktop or quicklaunch toolbar will lose it's normal icon and use the "default" windows icon, or often a wrong icon from a different program. Next boot up its back to normal.