Add Hardware Problems

My company recently purchased a couple of computers that
came with Windows XP installed. Every time I try to
install any hardware the following error message pops up:

"You can install only one device at a time."
"Another device installation is underway, when it is
finished you can try this wizard again."

I only attempt to install one device at a time and every
time I attempt this I get the above error message. Is
there something I can do to fix this problem?

Thanx
Mark