QUOTE(Baronic @ Aug 16 2009, 11:22 AM)
Did u install active sync?
I forgot to mention, the problem occurred when I was trying to install Mobile Device Center. I can't installed WMDC because it cannot locate the driver. Then I try connecting the device and reinstall, extract the drvupdate-x86.exe (WMDC installation file), run drvupdate-x86.msi, etc. Manage the install and able to run WMDC, but without driver whatsoever. Whenever I connect THD to PC, the "installing new device" pops up and run endlessly, and eventually fail to find a suitable driver and fail. When I tried to connect THD to PC, the external storage was also missing from My Computer.
Anyway, the problem is solved already. For those that had same difficulty, apparently, it is due to Vista unable to identify and locate the driver using the auto "installing new device" thingy. I try to let it search online for driver, also fail. Later, I just run "update driver", under Device Manager and let it search under windows/system32. It repeats for 4-5 times, until no new unknown device appear in Device Manager.
Then I run WMDC, connect my THD, the WMDC remains "not connected". MicroSD card finally appear under My Computer. Since my default setting for "USB to PC" is Disk Drive, the last driver (aka Touch HD) was not installed. The final step is to change to "ActiveSync" and enable the "Enable faster data synchronization". After that, the "Found New Hardware" appear, and installed THD driver. (Can see under Device Manager->Portable Device->Touch HD

).
Just my experience, in case others encounter similar problem, hope this will helps.

Took me one whole day to search and troubleshoot (seems like no one encounter such problem. Almost had me to download endless Vista hotfix

)
This post has been edited by Aurora: Aug 16 2009, 12:24 PM