flashplayer won’t install

This system is a Dell Dimension 8250 with 512mb Ram and Windows XP Home. There is ample hard disk free space.

The problem: We have tried to install Macromedia Flashplayer but even though no error messages show, it simply gets stuck in a never ending cycle of installing. Installation goes through as it should, but it is not there and continnually prompts to download and install it.

How can this be resolved?