I'm looking for a new patch management solution for my corporate environment and was wondering if anyone had some suggestions on what is good.

We currently use Shavlik NetChk and dont really like it. It locks up all of the time and it wont push any service packs for some reason. I'm not sure if the latest version fixes these, just would like to try something else.

We have about 2000 computers to manage and they are all Windows. I would like to find something that doesnt require a client to be installed.

Thanks in advance