Annoying problem with new hardware...

My rig, which until now was rock-stable, has been getting troublesome with the addition of a new hard disk. On adding the new (SATA) disk as an additional disk to my PATA boot disk and PATA storage disk, the computer was a bit iffy; and upon a restart, refused to recognize the two network cards (that's not to say it can't see them, just can't use them.)

This problem does not exist when you unplug the SATA disk and restart. This is the first time it's had a SATA disk in it.

Thoughts? (I have my suspicions but would like a second opinion).

Thanks in advance.

It sounds like a SATA driver problem.