  NGC604 is the largest HII-region in M33, second only within the Local Group
to 30 Dor, and is important as a laboratory for understanding how massive young
stellar clusters interact with the surrounding interstellar medium. Here, we
present deep (300ks) X-ray imagery of NGC604 obtained as part of the Chandra
ACIS Survey of M33 (ChASeM33), which show highly structured X-ray emission
covering ~70% of the full Halpha extent of NGC604. The main bubbles and
cavities in NGC604 are filled with hot (kT=0.5keV) X-ray emitting gas and X-ray
spectra extracted from these regions indicate that the gas is thermal. For the
western part of NGC604 we derive an X-ray gas mass of ~4300M_sol and an
unabsorbed (0.35-2.5keV) X-ray luminosity of L_X = 9.3E35 erg/s. These values
are onsistent with a stellar mass loss bubble entirely powered by about 200
OB-stars. This result is remarkable because the standard bubble model tends to
underpredict the luminosity of X-ray bright bubbles and usually requires
additional heating from SNRs. Given a cluster age of ~3Myr it is likely that
the massive stars have not yet evolved into SNe. We detect two discrete spots
of enhanced and harder X-ray emission, which we consider to be fingerprints
from a reverse shock produced by a supersonic wind after it collided with the
shell wall. In the eastern part of NGC604 the X-ray gas mass amounts to
~1750M_sol. However, mass loss from young stars cannot account for the
unabsorbed X-ray luminosity of L_X = 4.8E35 erg/s. Off-center SNRs could
produce the additional luminosity. The bubbles in the east seem to be much
older and were most likely formed and powered by stars and SNe in the past.
