engine cranks but won't start.

I drive a 1998 Volvo S-70 which I have regularly maintained but today I wen t to leave and it cranked but wouldn't start. The outside temp was very ho t and humid so maybe that was a factor but strangely the W light on the tra nsmission was on and I couldn't get it to go off even pushing the other set tings. Once before this happened and by rocking the car I got it to go bac k to its normal setting. This may be coincidental but wondering it there c ould be a transmission problem that was preventing it from starting? Thoug hts?