I have computer with Seagate IDE hard drive. I have decided to buy SATA PCI card and to connect Western Digital SATA hard drive. I hoped that this will improve performance of my computer. Unfortunately, when I tried to install Windows XP it did not recognize any hard drive. So, I wonder if SATA and IDE devices can exist together.
They can exist together. First thing you should do is to enable SATA and IDE in BIOS. This will help motherboard to recognize both devices and to use them. Second, during Windows installation you will be prompted (at the very beginning) to load third party SATA driver. Press F6 and load drivers that came with your hard drive or SATA PCI card. After this Windows will recognize both devices and utilize them.