Windows Firewall Fails to Start At Windows Vista Startup.

If Windows Firewall service does not start automatically at Windows Vista startup in your computer, then here are a few effective trouble-shooting steps are given :
First scan your Windows Vista computer fully for malware using a good anti-virus and an anti-spy utility. If you have installed a third party firewall or a Security Suite in your Windows Vista computer, then that could also be the cause for this problem.
Next, type services.msc in Windows Vista's Start Menu instant Search Bar and hit Enter to open up Services window.From the Windows Services menu ensure that the Windows Firewall Service is started and set on Automatic. Also ensure that the Remote Procedure Call Service is started and set on Automatic in Windows Services menu.

Now you also have to ensure that the Windows Firewall Authorization Driver (mdsdrv.sys) is running properly in Windows Vista.For this task, type in devmgmt.msc in Windows Vista instant search bar and hit Enter to open Windows Device Manager. In views tab check on Show Hidden Devices and also show Devices By Connection.
Locate Windows Firewall Authorization Driver in the opened list and double click on it to open its Properties box. Click on Driver tab and ensure that the process is started and startup type is Demand. if it is correct click OK and then reboot your Windows Vista computer.You can see that your Windows Vista Firewall service should be working OK now.

If the above troubleshooting techniques does not help to solve your problem in Windows Vista, then run Group Policy Result Tool to check if there is a firewall policy blocking it. Type in gpresult -z in Windows Vista instant Search Bar,and then right click on the result and run it as Administrator. Check under Resultant Set Of Policies For Computer, especially under Security Options.You can also type the following run commands in Windows Vista's Start Menu Search Bar and hit Enter to check Windows Firewall settings.