Often ports such as SATA, memory, PCI-E that have not been used recently (or ever-especially 3 years); tend to build up with dust, if you haven't used a port for some time, blow them out to clear out the dust and debris.
It wouldn't hurt to do a thorough cleaning of all your computer internals on this 3 year-old system.
Also wouldn't hurt to use all new cables for new components, peripherals.
Dell Inspiron about 3 years old running Vista Home Premium. I installed a second HD (SATA) and connected to SATA port 2 with new cable - didn't recognize drive on BIOS screen. I disconnected the CD burner from port 1 and plugged new HD into it using the same new cable - it works fine.
Plugged CD burner into ports 2 or 3 using its old cable without recognition. BIOS screen always says nothing is recognized in these ports. As a result I have either the new HD or a CD burner - this is not acceptable.
I've upgraded the power supply from 500 to 800 watts to be sure there won't be low voltage problems. That works fine, too. The old and new cables all work OK. I'm careful about securely plugging into the sockets. Ports 2 and 3 have never been used before.
How do I enable these ports 2 and 3 - or is that the problem? I have a new DVD burner to install in port 3 as well but am waiting to get the first problem fixed. Thanks for any help on this - it's getting urgent to have this work.