feat: Add troubleshooting guide for Apache startup issues after PHP version switch

Author: pphatdev

docs/apache-wont-start.md

@@ -0,0 +1,78 @@
+# Apache Won't Start After Switching
+
+## Problem
+
+Apache service fails to start after switching PHP versions.
+
+## Cause
+
+Apache processes may still be running in the background, or there might be configuration issues with the new PHP version.
+
+## Solutions
+
+### Step 1: Check for Running Apache Processes
+
+```powershell
+Get-Process -Name httpd -ErrorAction SilentlyContinue
+```
+
+### Step 2: Kill Any Remaining Apache Processes
+
+```powershell
+Get-Process -Name httpd | Stop-Process -Force
+```
+
+### Step 3: Try Switching Again
+
+```powershell
+phat switch [version]
+```
+
+## Additional Troubleshooting
+
+### Check Apache Error Logs
+
+Look for detailed error messages in:
+
+```
+C:\xampp\apache\logs\error.log
+```
+
+### Verify PHP DLL Files
+
+Ensure the correct PHP DLL files exist in the PHP directory:
+- For PHP 7.x: `php7ts.dll` and `php7apache2_4.dll`
+- For PHP 8.x: `php8ts.dll` and `php8apache2_4.dll`
+
+### Verify Apache Configuration
+
+Check that `httpd-xampp.conf` has the correct PHP module configuration:
+
+```
+C:\xampp\apache\conf\extra\httpd-xampp.conf
+```
+
+Look for lines like:
+```apache
+LoadFile "C:/xampp/php/php8ts.dll"
+LoadModule php_module "C:/xampp/php/php8apache2_4.dll"
+```
+
+## Manual Apache Control
+
+If automatic switching fails, you can manually control Apache:
+
+**Stop Apache:**
+```powershell
+C:\xampp\apache_stop.bat
+```
+
+**Start Apache:**
+```powershell
+C:\xampp\apache_start.bat
+```
+
+## Related Resources
+
+- [XAMPP Documentation](https://www.apachefriends.org/docs/)
+- [Back to Troubleshooting Index](TROUBLESHOOTING.md)