What the!?!? Workstation’s display turn upside-down &viruses are detect!!

This morning I copied a *.bmp file for my Windows XP SP2 desktop wallpaper, after I done that, the display turn upside-down with the resolution 800×600 (32bit color), so as the mouse cotrol, wallpapers, everything upside-down…
Then I try to change the resolution to 1024×768 (32bit color) everything back to normal, just the wallpapers doesn’t show up follow by keeps on poping out “Rundll.exe” is accessing “a:” for the *.bmp that I just copied, after that my TrendMicro Office scan poped up saying that there is 2 virus detected but didn’t show what is the virus’ name…
Does anyone have some advice to share? Thousand thanks in advance!!