Trouble Loading New Programs

I have a new computer running XP home edition and am
trying to load programs into the system. I have a number
of programs loaded and they are running just fine.
However, after having some modem issues and installing a
new hardware based modem, I am having difficulty loading
additional programs. They start to load and then the
loading process just hangs. Since it has happened on
more than one program, I wonder if there isn't something
in XP that has been clobbered. Any suggestions?