you won't lose HD data, but i don't know how you would reset the password. sometimes you won't see the battery, but you will see a jumper for it.
</font color=red><b><font color=orange>my sys:
mobo: Abit AN7 @ 442 FSB
CPU: AMPm 2600+ @ 4100+
ram: crosair xms @ 1:1 running 2.5-3-3-6
HDD: two raptors on raid 0
vid: 9800pro @ 467mhz GPU and 834mhz ram