You're getting bit by the Asus "Manageability" feature, DMI 2.0. You can see this listed in the green table near the start of your mobo manual.
I did some hunting on Yahoo, and it seems "Verifying DMI Pool Data" has been around Windows for a long time, mostly in Windows 9X. But you say you're running XP.
According to PhoneixBIOS user guides and other sources, DMI, the "Desktop Management Interface", is a facility (or part of one) for administering groups of enterprise computers. I think somehow you've managed to get this turned on, but your PC isn't set up to be managed, and so stuff probably sits there until it times out.
Near as I can figure, DMI is embedded in your mobo BIOS. When your mobo boots, DMI goes out and probes the hardware to see what's in it, and collects all that data, probably into a "pool". If that's correct, "verifying DMI pool data" might mean checking what's known, against what isn't known... which might include that new HDD you added. Sorry, I'd need to study the SMBIOS specs a lot more to make any real sense out of it.
I did find this article, Microsoft 287553
which simply says it's a hardware problem.
I poked around some more and think I found implications that DMI is somehow related to Plug-and-Play. For Windows XP you should have that disabled, so maybe you might want to have a look at your BIOS Advanced- PCI PnP screen. There's a field there called "Resources Controlled By", and I think Auto/ESCD means Plug-and-Play. So you might want to switch this to Manual.
I also suspect you might be able to clear the whole thing up by either trying the BIOS Exit- "Load Setup Defaults", or first clear CMOS using the jumper and then load defaults. If you do either, first carefully walk through every BIOS screen and write down everything, so you can have a clue what to do if something isn't working right afterwards.
I don't really see any other feature in this BIOS, to force detection of new SATA drives, only IDE drives.