There have been reports of slow boot ups when running Windows Vista…  But so far far, it appears to be a variety of issues…  One issue is the GPCLIENT service taking an long time to startup during boot up…

1. Check your DNS settings on the Vista client, and make sure that the Fastest DNS server is first in the list.  You may want to add the OpenDNS DNS servers to your DNS list, to help diagnose a local DNS issue.
2. Turning off auto-tuning on the Vista client may help.  From a command prompt, type:
   netsh interface tcp set global rss=disabled
   netsh interface tcp set global autotuninglevel=disabled
3. Make sure that Vista SP 1 or later is installed on the system, and that the system is fully patched.
4. If the previous did not work, then try the Performance Self-Tuning & Diagnsotics.  Open the Windows Menu, Control Panel, System Maintenance, Performance Information & Tools, Advanced Tools.  Choose Performance Self-Tuning & Diagnsotics.
5. Consider setting the Network Card Speed & Duplex, instead of Auto-negotation.  That may help resolve the issue in some cases.

Please feel free to let me know if you have any alternative suggestions, or comments…