I just replaced the hard drive on a Dimension 4600. I hooked up everything like it was on the old drive and turned the pc on with the XP CD. I also upgraded the memory from 512 to 1024.  The memory was recognized when it started but the hard drive wasn't.  It did go to the XP setup and I selected "Enter" to install Windows. After the install it doesn't see the hard drive. When I went to the BIOS it doesn't have the hard drive in the boot sequence.  How do I get the new hard drive to show up in the BIOS.