SQL 2005 Express not working on your (Fasthosts) dedicated server?
Got a £60 per 1/2 hour personal engineer booked?? CANCEL IT!!!
If you like me and many others have rented a dedicated box with a web host and are planning to use SQL 2005 Express cause its up to your requirements (I do!), there is a small point that very few people realise is the cause of the all too familiar "SQL Server is unavailable or does not exist" message.
After ensuring that you have remote connections open and have enabled sql accounts as well as windows authentication (see: http://support.microsoft.com/default.aspx?scid=kb;EN-US;914277 or http://blogs.msdn.com/sqlexpress/archive/2005/05/05/415084.aspx) you may still be struggling (especially if you use Fasthosts). The reason is that you will probably find your firewall is blocking UDP packets which is what the SQL Browser uses to server Management Studio (etc) with. To get round this you can force SQL Express to use a TCP port. All you need to do is set it in the appropriate properties page by following this knowledge base article: http://support.microsoft.com/kb/328306
Now seeing as I've just saved you £60 maybe you should PayPal me £30 for the help!!!!
Update: It seems MS has been moving some settings around in the Standard version of SQL 2005, so in case this is effecting you and the above hasn't worked, make sure you check the following (thanks AC):
Administrative Tools > Local Security Policy > IP Security Policies on Local Computer > Default Security Policy > Double-click "MSDE/MS SQL" > Filter Action tab > change to Deny or Permit