Local connection failure: please help

I Have SQL Server 2000 local installed on a Windows XP SP2 machine,
Dutch version.
SQL Server first connected fine via the default settings 'Use Windows
Authentication'. I use it to test VB.Net practices, which went fine
for a while. I am busy preparing for the 70-310 exam.
Then I had problems with a VB.Net (a webservice) application
connecting to SQL server local. Via a newsgroup someone advised me to
change the login to 'Use SQL Server Authentication'. I used the
default password 'sa' and no password. I couldn't get any connection.
I tried with 'Administrator', but no connection.
When I tried to set it back to 'Use Windows Authentication' I get the
message Connection Failed, check SQL Server registration properties.
When I tried to open the properties of the local SQL Server (LOCAL)
(Windows NT) via the Enterprise Manager I get error 1069. I tried
several usernames, nothing helps. I didn't change the default, so it
should be 'sa' without a password?
Please help, I am stuck for days now.
RoyWell, the only solution was to re-install SQL Server and restore the
databases...
On Thu, 20 Jul 2006 14:16:09 +0200, RC <roycoumans@.hotmail.com> wrote:

>I Have SQL Server 2000 local installed on a Windows XP SP2 machine,
>Dutch version.
>SQL Server first connected fine via the default settings 'Use Windows
>Authentication'. I use it to test VB.Net practices, which went fine
>for a while. I am busy preparing for the 70-310 exam.
>Then I had problems with a VB.Net (a webservice) application
>connecting to SQL server local. Via a newsgroup someone advised me to
>change the login to 'Use SQL Server Authentication'. I used the
>default password 'sa' and no password. I couldn't get any connection.
>I tried with 'Administrator', but no connection.
>When I tried to set it back to 'Use Windows Authentication' I get the
>message Connection Failed, check SQL Server registration properties.
>When I tried to open the properties of the local SQL Server (LOCAL)
>(Windows NT) via the Enterprise Manager I get error 1069. I tried
>several usernames, nothing helps. I didn't change the default, so it
>should be 'sa' without a password?
>Please help, I am stuck for days now.
>Roy