Agreed. Make sure you have a PK on the table. If it were me, I would make an integer field as the primary key and add a unique nonclustered index to the computer name field so SQL won't worry about sort order based on a string field.

One more tip - use an appropriate data type for the computer name before you index it. If you're storing computer names, you probably don't need an nvarchar(max) or anything like that. More companies have strict policies on computer names, so get yours and go 2 bytes beyond it for when they exceed their own limit.