I had a similar issue where when I first took the game up I wasdriving consistently straight at around 250 yards and then as I became more serious and started tweaking my swing my iron game improved significantly but my driver and fairway wood went hay wire. Every time I adjusted something in my swing something different would happen - push slice, hook - you name it I probably hit it. The worst thing is that by trying to adjust my swing to get my driver to work I through my iron play out of wack as well.

This went on for a few months before I finally had enough and dragged myself to the local golf shop to see what was happening on the launch monitor. It turns out that my swing speed had increased to over 100mph and the regular flex shaft I had on my woods didn't suit my swing anymore. I purchased a new driver with a stiff shaft with a higher bending point and low and behold I'm back to driving straight again. The best thing is that now I'm back to my natural swing my iron play has fixed itself as well.