Unable to install SQL Server 2005 September CTP (from a clean Windows XP)

The September 2005 SQL setup is refusing to continue the install. The log says:

Microsoft SQL Server 2005 CTP 9.00.1314.06
==============================
OS Version : Microsoft Windows XP Professional Service Pack 2 (Build 2600)
Time : Wed Sep 21 09:48:10 2005
The current system does not meet the minimum hardware requirements for this SQL Server release.

HOWEVER, The system exceeds the requirements: Pentium 4, 3GHZ, 512MB RAM, 50GB free in HD, DVD/CD, etc.

I am running on a clean install of Windows'XP, with IIS 6., Office 11.
Caveat: I am trying the install from a VirtualCD/DVD, which in previous set ups worked fine

[663 byte] By [JuanVargas] at [2007-12-17]