I regularly have some clients with network problems.  Using this article I solved a lot of problems.  The article How to troubleshoot TCP/IP connectivity with Windows XP describes a lot of useful tools to determine where the network problem exists.

If you suspect problems with the Tcp/IP stack.  You can use the article on TechNet: Reset the Internet Protocol (TCP / IP) stack in windows XP.  Because the TCP/IP stack is considered a core component of the Windows XP operating system, you cannot remove it.  You need to follow the instructions given in the article.  Being...

netsh int ip reset c:\resetlog.txt

Today, I couldn't attach a database of my previous pc to my new MSSQL Server installation.

I got this strange error message in Microsoft SQL Server Management Studio.

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I got this error message:

Attach database failed for Server 'STELLA'.  (Microsoft.SqlServer.Smo)

For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=9.00.3042.00&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Attach+database+Server&LinkId=20476

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ADDITIONAL INFORMATION:

An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo)

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Unable to open the physical file "E:\MSSQL\InfoBase.mdf". Operating system error 5: "5(error not found)". (Microsoft SQL Server, Error: 5120)

For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=09.00.3054&EvtSrc=MSSQLServer&EvtID=5120&LinkId=20476

Solution

The solution was very easy.  Launch Microsoft SQL Server Management Studio as Administrator.

Problem

When i installed windows Vista, Live Messenger (and various other applications) where not working properly. They could not connect to the internet. 

Using the Internet Connectivity Evaluation Tool might help detecting any problems at home networks.  It did for me.  I found out that my router is not supporting "Universal Plug and Play" (UPnP).

Solution

A long story short:
Apparently the problem is the TCP auto tuning feature of Windows Vista.
On technet I found this: "Network connectivity may fail when you try to use Windows Vista behind a firewall device".  It helped.

Conclusion

Although everything is working for now, our router is still not "up-to-date".  I'm consider buying a new router.