hi i am pepemorph and i hope you guys can help me on my problem when i play blood it runs fine but when i go to window mode and i click on another window in front of it and click back on dosbox it gets a split screen.dosbox gets no error message it simply plays it in split screen. oh and also when i get back on the dosbox window with no window behind it, it goes back back in place so i hope you guys can help

here are my specs.
processor: AMD Athelon processor 4000+ 2.60ghz
memory:1.00 gb ram
video board:nvidia geforce 6150se nforce 430 NVIDIA compatible
sound board:realtk high definition audio
os: windows vista home premium
game:one unit whole blood
description of problem:split screen when running another progam at the same time when running dosbox
reproducablity:always
sound mode:soundblaster awe32
video mode: all video modes
version of dosbox: dosbox cvs pre compiled gulikoza's 25.02.2008 extract version not installer
steps already taken to solve problem:read readme changed diffent video modes.
please help thanks in advance?