I used SpybotS&D's task scheduler, which basically served as the impetus for me to learn all about Windows XP Scheduled Tasks. At first, I set up a schedule task to update SpyBotS&D, followed by a 2nd Scheduled Task to scan the hard drive (a much longer task) 30 minutes after the update. I gave 30 minutes leeway because I could not anticipate the things that might delay the update. However, I found that DOS commands could be concatenated using the ampersand symbol. So I changed the following two tasks to one task:
  • "C:\Program Files\Spybot - Search & Destroy\SDUpdate.exe" /autoupdate /autoclose
  • "C:\Program Files\Spybot - Search & Destroy\SpybotSD.exe" /AUTOCHECK /AUTOFIX /AUTOCLOSE

The single concatenated command is:
"C:\Program Files\Spybot - Search & Destroy\SDUpdate.exe" /autoupdate /autoclose & "C:\Program Files\Spybot - Search & Destroy\SpybotSD.exe" /AUTOCHECK /AUTOFIX /AUTOCLOSE
If it worked, this compound command has the benefit that it doesn't have to blindly wait for 30 minutes between the update and the scan. This leaves more time throughout the night for scheduling of other malware scanners. Furthermore, if for some reason the update is delayed for more than 30 minutes, the scan still won't happen before the update.

However, it doesn't seem that this compound command is working. The update happens so fast that there is no "Running" indicator in the Scheduled Task folder, and it doesn't show up in the task manager. In itself, this is fine (assuming that it ran). However, it doesn't seem that the scanning part of the compound command works because (again) it doesn't show as Running in the Scheduled Task folder and doesn't show up in the Task Manager. Scanning is a lengthy process, and it *should* show up in both these ways -- it shows up when it isn't folded into the compound command.

I've reverted back to not having a compound command, but I was wondering if someone could shed some light on the reason why the scan can't be hitched on to the tail of the update command, as I have tried to do in the compound command?

I am running Windows XP SP3.