Well, I haven't ever had Vista crash (yet), so not sure why you have the issue. It may be a router issue, or a Windows issue, or an Antivirus/Anti-spyware issue, or something else.
Check your error logs in Windows to see what they tell you...
Run eventvwr.exe from your start menu, then click on Windows Logs and then try both Application and System and see if there are any actual Errors (not just Information). That may help narrow it down.