How does your computer provide eSATA functions? Is it done with a special chip by Via, Silicon Image, nVidia, or some such company in addition to the "regular" SATA ports provided by the main southbridge chip? Most mobo's do it this way - using a special extra chip. If that is how your mobo works, check carefully in the documentation of drivers for the motherboard devices. These usually are on a CD of stuff that came with the mobo. The chip is considered a device on the mobo and Windows will need to have a device driver for it loaded in order to use it.