Here's an alternative:
SELECT u.*, n.ID, n.notes
FROM UserTable u
INNER JOIN Notes n ON
(u.lastaccounttype = 'account1' AND n.account1 = 1) OR
(u.lastaccounttype = 'account2' AND n.account2 = 1) OR
(u.lastaccounttype = 'account3' AND n.account3 = 1) OR
(u.lastaccounttype = 'account4' AND n.account4 = 1) OR
(u.lastaccounttype = 'account5' AND n.account5 = 1)
Edit: Added the sql and /code tags around the SQL.
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".