When you right click each task and select Run from the menu
what happens?
Is there a possibility that the computer will be in standby
mode when you've scheduled these tasks to run? If so, check on
the following settings:
Open Scheduled Tasks. Right click one of your maintenance tasks
and select Properties. Click on the Settings tab. Make sure
there's a check mark in the box next to "Wake the computer to
run this task". Next, click on the Task tab. Make sure there
isn't a check mark in the box next to "Run only if logged on".
Click OK. Do this for each of your scheduled tasks.
Here are a few articles that provide more info on running Disk
Cleanup and Defrag as scheduled tasks. You might want to double
check that you've properly configured your tasks.
How to Automate the Disk Cleanup Tool in Windows XP
http://support.microsoft.com/default.aspx?scid=KB;en-us;315246
Automate Disk Cleanup using Task Scheduler in Windows XP
http://windowsxp.mvps.org/Automate.htm
How to Automate Disk Defragmenter Using Task Scheduler Tool in
Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;555098
Finally, following up on a point I made in my earlier response:
Scheduled Tasks cannot run with a blank password
http://support.microsoft.com/default.aspx?scid=kb;en-us;310715
Good luck
Nepatsfan
In (e-mail address removed)