I ran into a problem with triggers wich stopped me from logging into my databases. I hoped that reinstalling the software would fix the problem but instead it created a diffrent problem, my sql server does not see (local) anymore. Note that i installed SQL server with Visual studio 2010. So im am quite sure that i installed Sql server 2008 R2 Express, not 100% positive. I checked this by using;
osql -L Servers: 4720S_8\SQLEXPRESS
Some stuff that might help: I also ran into a diffrent problem when trying to manually connect to a specific database by browsing to it (a Database i ran fine before the problem) and it gave me;
Cannot be opened because it is version 661 This server supports version 655 and earlier.
I also had SQL server manager studio express installed. And as i am not quite sure what i did at the time i set all my servers up it is possible that i installed a second server with that tool instead of applying it to my excisting server.