|To burn a disk, probably the same requirements that a DVD burner asks for.|
To play a movie: 1GB of RAM, either an HDCP compliant video card or plain old VGA (non-HDCP DVI will not work), and a very fast processor, especially if the video card doesn't have hardware assist. Something like a Pentium D 950 or Athlon X2 4200. It's gotta be a dual core, I know that much for sure.
My Super P3:
Pentium III-S 1.4GHz @ 1.5GHz, 512K L2
X800XT All-in-wonder, overclocked to 580/600.
2 gigs of PC2100 RAM
QDI Advance 12 mobo, this baby rocks!
SB Audigy 2