Automating Maintenance Tasks

I need a batch file or executable that will automate basic maintenance tasks. There should also be a mechanism to email a report when the process is done outlining if the tasks were completed and with system information. This will need to run on Windows XP, Windows Vista, and Windows 7 machines as well as Windows Server 2003 and Windows Server 2008. 64-bit and 32-bit compatible. Different variations of the script can be used for different operating systems. The tasks that need to be automated include: System Audit (To be emailed in the report) Verification of Anti-Virus software Disk Check Disk Cleanup Disk Defrag Windows Update Disabling Windows Services Customizing system settings Making registry changes Making sure the Windows firewall is on and a few other tasks. I would assume that the hardest things to do would to be able to read and tell if the current anti-virus software is up to date, update it if necessary, install anti-virus software if nothing is installed, remove viruses in a virus vault. I can provide a detailed list of what exactly needs to be done.