WD MyBook not always detected by eSATA

I recently purchased a new external WD MyBook as well as an external SATA card. After inserting the card into a PCIExpress slot in my EVGA 680SLi motherboard, I installed the driver and everything seemed to work fine...the HD was being detected and data could be written to it. Subsequent to that I reformatted the MyBook for NTFS, but this is probably not relevant to my problem.

Every so often when I boot, during the sequence of boot actions the eSATA card will not detect the drive. This consequently causes Windows (XP Home) to take up to two minutes to load (it sits on the splash screen for quite some time). To rectify the situation I have to unplug the power cord from the hard drive for a few seconds and plug it back in. Then the drive is detected.

Is this a hard drive issue or is this being caused by my eSATA card. I forgot who manufactures the card (got rid of the box) and the card itself has no manufacturer name printed on it (how stupid is that?).

Any suggestions? If its the eSATA card, can anyone recommend a good one? I don't run RAID at all. I have three internal HDs (> 1TB), two of which are connected with SATA cables to the motherboard and one of which is connected with IDE cable.