Reformat destroys all data on a hard drive. Without an OS and drivers, the machine won't even boot up. Don't you have a restore disk or a restore partition on the hard drive? That's what's required to put the machine back in the same condition it was when purchased.
Start here: http://www.hitachigst.com/hdd/support/download.htm
(I wasn't able to find much on this site)
I suspect this is a Japanese market notebook, which support will have to come from Hitachi Japan ( www.hitachi.co.jp
I found this Google translated page for drivers for the Flora 270W. You have to click the download link first for the hardware device you want a driver for, then on the next page you have to scroll to the bottom left and click on the button that says Agree
(when the mouse cursor is positioned over it) to download the driver. The download button looks like this:
Here's the link:
that the download page contains drivers for XP AND
Vista so be sure to click on the one for Windows XP to get the correct driver.
Also, I cannot get FoxFire browser to display the page but IE7 works ok.