Avast! main service doesn't start - Windows XP firewall doesn't start

[Overnight]

Here is the problem when you start your computer :
- Windows XP Security Center system tray icon : "No firewall software is running on your computer at the moment"
- Avast! system tray icon is disabled with a red cross

Here is the cause : last downloaded VPS (virus definition update) is corrupted

Here is the solution :
- Start
- Control Panel
- Add/Remove Programs
- find Avast! antivirus
- click on "Remove"
- in dialog box, choose to "Repair"

Now a new VPS file is being downloaded and Avast! services' components are reinitialized : be sure to wait until the end of process which can take up to 5 minutes

- Now, Start
- Execute
- type 'services.msc' and click OK
- find "Avast! Antivirus" service, right-click and choose Restart
- finally, right-click on Avast! system tray icon and choose "Start resident protection"

Here you are !!

PS : if you read System log in Windows Event Viewer, you should find such an entry about Avast! Antivirus : "AAVM - initialization error: AavmStart: avworkInitialize failed"