The power light on my MESH tower is flashing. Why?

Not sure. It could mean a number of things. It could signify that the PC is in standby mode. Maybe someone wired up the case LED's incorrect and the hard drive light and power light are the wrong way round.

Have you still got your manual's? Try looking in there. Alternatively, try the Mesh support page: http://www.meshcomputers.com/Default.aspx?PAGE=RUNTIME_OLD_SUPPORT_HOME