Assign a different IRQ to the card in bios.
Or move the PCI card to a different slot.
Also, when you plug in your Esata drive, it's logical assignment may be lower than your boot drive, so the bios checks that first, can't find any boot info & reboots.
Or possibly ... the bios detects the drives correctly and boots from the correct drive, but windows loads the driver for your sil controller first, assigns your esata drive as the primary drive & falls over. God knows what sort of weird bugs windows has
I know that windows craps itself if there is any partition corruption, or it can't read a partition correctly, especially a problem when I'm switching around drives with mixtures of linux EXT2/3/4 partitions and windows NTFS/Fat32 partitions and windows expects a particular logical device & partition to be something (NTFS/FAT32), but it turns out to be something else (EXT2/3/4)