Qemu / Linux Host / Win7 Guest - Networking DHCP stopped working

Here is my current string.

qemu-system-x86_64 -device piix3-usb-uhci  -enable-kvm -soundhw all  -smp 4 -m 2048M -boot d -cdrom /dev/cdrom -drive format=raw,file=hd.img

Networking worked automatically and I could browse. It recently just stopped working for no reason.

QUESTION: Does qemu use dhcp to connect the guest with the host ? Whatever I configure I cant get it to work again.

Any rigorous method to get networking up in windows 7 guest? The online info does not help at all to describe how Qemu connects the guest with the host network.

Note: I tried manual configs and dhcp in windows network config tool under tcp/ip. I have no problem getting networking going on any windows native system, so I am proficient. My configs are therefore valid on the guest but seemingly not valid for qemu, as it doesnt connect through the host

I am part of Qemu group where these questions should go, but traffic is very low there recently with long waits for answers, so I try here.