I have just taken over a very important db (server 7) and found that the sa password is blank. If I put a password, would that affect anything ?

No affects overall-- Best Practice

something to consider

If any of you application are using the SA account and it is hard coded, this will be a problem. Other than that you should be okay.

Special note avoid using the SA account for anything. Create other user roles and permission for the needed tasks. Use the SA account as your life saver account

Jaime E. Maccou

Very true we should almost always not use SA a/c within our application.

Best Regards
Vadivel

MVP ASP/ASP.NET
http://vadivel.thinkingms.com