Most probably you will need to format the HDD to a FAT32 format. Here is a guide how to do that: http://products.wdc.com/support/kb.ashx?id=GTqqei
If this does not work out, you can try to connect a USB flash drive as g90814 already suggested.
It may not be a bad idea to check out the TV's manual and see what are the supported video files.
Most probably you will need to format the HDD to a FAT32 format. Here is a guide how to do that: http://products.wdc.com/support/kb.ashx?id=GTqqei
If this does not work out, you can try to connect a USB flash drive as g90814 already suggested.
It may not be a bad idea to check out the TV's manual and see what are the supported video files.