resolution changes to minimum after game exit

after i play some game sometimes the monitor resolution changes to the smallest value something like 1100 x 700 .. i must log out and log back in to user or reboot to get back my normal resolution 1920 x 1080 on my SyncMaster B2330HD monitor .
WHY and how do i fix this annoying problem

also .. my desktop background changes to white from some random image i put into the memory of images to shuffle
why ? and how to fix it

thank you

ok .. this has gone too far
now only 1/3 of my monitor shows icons and the rest are GONE ... vanished .. i have to log out and log back in to fix this but once that didnt help
im starting to think windows 7 is the buggiest windows that dont offer proper FIX !! -.-