Thanks for your reply, realborat.
Originally the Seagate Expansion external harddisk comes with NTFS format, so there is no problem for my PC (WinXP) to access. When I tried to format it via linkstation website into FAT32 format, it failed. Tried to restart both linkstation and seagate, then format again, no luck still failed.
With this format failure, right now I even cannot see it when plugged into my PC via USB port.
Anyway, thanks for your input. I already decided to return the seagate disk even I really need one for backup and the seagate disk did have a very good review.