Could you be more specific about where the installation hangs - is it during the hardware detection stage for example?
If this is the case remove any graphics or pci hardware if possible. I am unable to install windows with my Ati Radeon 9800 Pro card, so I swap it out for an old avance logic gfx card, and then install the 9800 after a sucessful winxp install.
Other than hardware troubleshooting, the aforementioned memtest and cd drive swap are both well worth checking.