The customer was having trouble with their client systems which was running the application from a Terminal Server.  The problem stemmed from the fact that the Terminal Server itself became corrupted due to tampering. We uninstalled and reinstalled the Terminal Server; Re-connected the client desktops; verified that their HR/Payroll data was still intact and verified their SQL Server user account security was intact; verified database backups were stable and up to date, in general the system was healthy, then proceeded to restore payroll for over 2000 users.