Bitjet,

I knew nothing about pool mining, until last night, and I am also running Windows 7 with an ATI 5770.

Following the instructions (see the section titled "How to Start") on https://deepbit.net/, I was up and running in about 30 minutes.

I had to download the OpenCL drivers from ATI's website, before I could use my GPU, and I used the GUIMiner to handle all the command line options for me. I found the GUIminer by following the link, on this post: http://forum.bitcoin.org/?topic=1334.0, under the heading "GUI."

I'm certainly no expert, but having been successful so recently, you're welcome to ask any specific questions you might have while setting it up.

Good luck!

P.S. By the way, I used the Geeks3D GPU Caps Viewer at http://www.geeks3d.com/20090414/gpu-caps-viewer-170-available-with-cuda-support/ to monitor the temperature of my GPU while I set it up. I found that adding "-s0.01" to the "Extra flags" field, gave me a little peace of mind, at a cost of about 10Mh/s. I may remove that, as it seems the GPUs fan is doing a good job of keeping up with the temperature. (Despite my signature, it seems I'm averaging about 120Mh/s... don't know why the signature shows less.)