Frank Hamelly solves GP10 SP2 User Login Hangs at Homepage Rendering.
Instead of Google Frank, try MyGPSearch.com for items like this!
GP2themax – Helping users get the ‘max’ from Dynamics GP: GP10 SP2 User Login Hangs at Homepage Rendering
Archived post from 2011. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.