Is there a piece of software that can do all of the following in one or at least most of them?
-Billing system
-Accounting and recordkeeping
-Support system
-Order processing

Most billing software will handle billing, support, and orders. However you might have to look hard to find something that also offers accounting and recordkeeping in the same package.

Can you give a good example please?

phpCoin (www.phpcoin.com and in Fantastico)

ClientExec (www.clientexec.com)

ModernBill (www.modernbill.com)

And many others.

Thanks, I think that I will start off with ClientExec and see how it goes.

I find AWBS (formally drams) quite nice and complete, the demo looks great, but haven't use it yet. I wonder any comment from those who are using or try out AWBS.

www.dramsystem.com

hsphere does it all and its really quite good, we use it now.

AWBS 2.0 is really nice. We use it in a Windows environment with Helm as our CP, Authorizenet for payment and Enom for domains. It appears most AWBS customers are Linux but it works equally well in both environments.

Nice system and getting even better. ;)