odd question, but I was wondering what happens if I install a formatted drive with data (esata), that has the same drive letter as an internal drive (sata).
Is the eSATA drive from another system? If so, when you connect it the OS will just assign another drive letter to it that doesn't conflict with the internal SATA drive.
Let's say you have one system with an internal SATA drive (assigned C: ) and an eSATA drive (assigned D: ). You have another system with two internal SATA drives (assigned C: and D:, respectively). If you connect the eSATA drive to the second system, it's not like Windows will freak out because it sees two D: drives...it'll just assign the new drive another letter that's not being used.