When attempting to start the DefaultAppPool in IIS 7.0 on Windows 7 Professional, you might encounter the frustrating error: Service WAS was not found on computer '.'. This typically indicates that the Windows Process Activation Service (WAS) is either not installed or not functioning correctly.

First, verify if WAS is installed on your system:

sc query WAS

If the service isn't found, you'll need to install it through Windows Features:

dism /online /enable-feature /featurename:WAS-ProcessModel /featurename:WAS-ConfigurationAPI /featurename:WAS-NetFxEnvironment

If WAS is installed but still not working, try these solutions:

1. Restart the service:

   net stop WAS
   net start WAS

2. Repair IIS components:

   %windir%\system32\inetsrv\appcmd.exe list apppool

3. Check dependencies:

   sc qc WAS

For persistent issues, examine the Windows Event Log for detailed errors:

eventvwr.msc

Look for entries under "Windows Logs > System" related to WAS or IIS.

To avoid future WAS-related problems:

• Regularly check IIS configuration backups
• Monitor system resources to prevent service crashes
• Keep Windows and IIS updated with the latest patches

When working with IIS 7.0 on Windows 7 Professional, you might encounter the frustrating error message: "Service WAS was not found on computer '.'" while trying to start DefaultAppPool. Let's dive deep into understanding and resolving this issue.

The Windows Process Activation Service (WAS) is a fundamental component of IIS that manages application pool configuration and worker processes. When this service is missing or corrupted, IIS can't function properly. Common causes include:

• Partial or corrupted IIS installation
• Windows updates interfering with system components
• Accidental service disabling
• Permission issues in the Windows registry

Before attempting any fixes, let's check if the service exists and its current state:

sc query "WAS"
net start "WAS"
Get-Service -Name "WAS"

Method 1: Re-register WAS Components

Open an elevated command prompt and run:

%windir%\system32\inetsrv\appcmd.exe list apppool
%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i
net start WAS

Method 2: Repair IIS Installation

1. Go to Control Panel > Programs and Features > Turn Windows features on or off
2. Uncheck "Internet Information Services" and restart
3. Re-enable IIS features including:

   - Web Management Tools
   - IIS 6 Management Compatibility
   - IIS Metabase and IIS 6 configuration compatibility

4. Restart your computer

Method 3: Manual Service Registration

If WAS is completely missing from services.msc, try registering it manually:

sc create WAS binPath= "%systemroot%\system32\svchost.exe -k iissvcs" type= share start= auto
sc description WAS "Windows Process Activation Service"
sc config WAS depend= HTTP/NetTcpActivator/NetPipeActivator

For persistent issues, check the system event logs for related errors:

Event Viewer > Windows Logs > System

Look for events with source "Service Control Manager" or "WAS". Common event IDs include 7000, 7009, or 7023.

To avoid future occurrences:

• Create regular system restore points before IIS configuration changes
• Use PowerShell to backup IIS configuration:

  Export-WebConfiguration -Name "MyIISBackup" -PhysicalPath "C:\Backups"

• Consider upgrading to a newer Windows version if possible