Hi,
Couple of things:
1) One of the comparator inputs is on AN0, turn the comparator off, CMCON=7
2) Don't mess with the GO/DONE bit (bit 1 in the ADCON0 register) if you're using ADCIN - it'll handle it for you.
3) The LED will only be on when w0 is 100 and 100 only, might be easy to "set" the value to 100 in a simulator but not in a real circuit. Try IF w0 > 100 instead.
4) I never never seem to remember when to use left- and when to use right justified, if you're like me try both and see what happends.

/Henrik.