problem when VS 2008 setup

Hi,

Yes I have followed the link but I didn't understand the contents well since there are number of probabilities which I think I am not having them .

during the start of the setup It says that "setup detected Microsoft Windows installer 3.1 "which is required ...etc

for example installation  requires before setup , to close any application  running on even if I am not running any on my pc. I don't know whether some hidden processes running in background

I have restarted my pc many times in case it would allow setting up but no use .

please help