  We present XMM-Newton observations of two hyperluminous IRAS galaxies
(L_Bol>1E13 L_sun), neither of which was previously detected by ROSAT.
Published models of the infrared SEDs imply that a starburst and obscured
quasar contribute equally to the power of each source.
  IRAS F12514+1027 (z=0.30) is detected in 18.6 ks with 130 EPIC-pn counts over
0.2-12 keV. The soft X-ray spectrum exhibits thermal emission from the
starburst, with T=0.3 keV and L(0.5-2.0keV)=2.1E42 erg/s. With its Fe K-edge,
the flat continuum above 2 keV is interpreted as cold reflection from a hidden
AGN with an intrinsic L(2-10keV) of at least 1.8E44 erg/s. Comparison with the
infrared power requires that the X-ray reflector subtend ~2pi/5 sr at the
central engine. IRAS F00235+1024 (z=0.575) is not detected by the EPIC-pn in
15.9 ks; the limits imply that the starburst is X-ray weak, and (for the AGN)
that any hard X-ray reflector subtend <2pi/5 sr. The direct lines of sight to
the AGN in both objects are Compton-thick, and the presence of a reflection
component in F12514+1027, but not in F00235+1024, suggests that the AGN in the
latter object is more completely obscured. This is consistent with their
Seyfert-2 and starburst optical spectra, respectively.
