equation solving – Mathematica finishes running but produces no output


Apologies for the very noob question, but I was unable to find anything just googling.

I am trying to solve a system of non-linear equations symbolically using Solve. My input is

Solve(a1*rtn + a2*rtc + a3*in + a4*ic + a5*rdc + a6 == 0 && 
a7*rtn + a8*rtc + a9*in + a10*ic + a11*ic*rtc + a12*in*rtn + a13 == 0 &&
a14*in + a15*ic + a16*in*rtn + a17 == 0 &&
a18*rtn + a19*rtc + a20*ic + a21*in + a22*rdc + a23*in*rtn + a24 == 0 &&
a25*in + a26*ic + a27*in*rtn + a28*ic*rtc + a29 == 0, {rtn, rtc, rdc, in, ic})

Running this in my notebook takes about 10 sec, and afterwards there is no output (the ‘Out(*)=’ line is completely missing). Moreover, after running, the syntax highlighting that shows me what is a variable and what is a symbol disappears (all the text becomes black).

Does this mean there is a problem with my system? I checked with Nsolve by putting in some arbitrary values for the a*s, and that gives solutions with no problem…