You may experience connectivity issues or performance issues when you connect a Windows Vista-based mobile PC to a non-Vista certified wireless access point or router

Source: Microsoft Support

RAPID PUBLISHING ARTICLES PROVIDE INFORMATION DIRECTLY FROM WITHIN THE MICROSOFT SUPPORT ORGANIZATION. THE INFORMATION CONTAINED HEREIN IS CREATED IN RESPONSE TO EMERGING OR UNIQUE TOPICS, OR IS INTENDED SUPPLEMENT OTHER KNOWLEDGE BASE INFORMATION.

You may experience random connectivity issues when you connect a Windows Vista-based mobile PC to certain Wi-Fi hotspots, access points, or routers. 

These connectivity issues include the following:

•             The wireless network connection is dropped.

•             You experience poor performance.

You experience this issue if the Windows Vista-based computer is connecting to a wireless access point or router that is not fully vista compatible.

=============================

This issue occurs if the Wi-Fi hotspot uses wireless access points or routers that do not fully support the whole networking feature set and requirements of Windows Vista.

Common feature set support issues can be caused by a lack of full support for:

·         UPnP

·         Quality of Service (QoS)

·         NAT type

·         IPv6

·         Teredo

·         6to4 tunneling

Contact the router or access point hardware vendor to ask about a firmware update or Windows Vista Certified device status.

MICROSOFT AND/OR ITS SUPPLIERS MAKE NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY, RELIABILITY OR ACCURACY OF THE INFORMATION CONTAINED IN THE DOCUMENTS AND RELATED GRAPHICS PUBLISHED ON THIS WEBSITE (THE “MATERIALS”) FOR ANY PURPOSE. THE MATERIALS MAY INCLUDE TECHNICAL INACCURACIES OR TYPOGRAPHICAL ERRORS AND MAY BE REVISED AT ANY TIME WITHOUT NOTICE.

TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, MICROSOFT AND/OR ITS SUPPLIERS DISCLAIM AND EXCLUDE ALL REPRESENTATIONS, WARRANTIES, AND CONDITIONS WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING BUT NOT LIMITED TO REPRESENTATIONS, WARRANTIES, OR CONDITIONS OF TITLE, NON INFRINGEMENT, SATISFACTORY CONDITION OR QUALITY, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, WITH RESPECT TO THE MATERIALS.