Updates? Do you mean Windows Update?
Do not run Windows Update on a Windows Embedded. Windows update is intended for full Windows 7 not Windows Embedded 7. Since WES7 is a stripped down version of Windows 7, you might be patching something that isn't in the OS anymore and causing blue screens or unstable operation. You should use the pre-packaged Wyse Device Manager updates for WES7. These updates are specifically for Embedded.
http://www.wyse.com/serviceandsuppor.../Z90D7(Windows Embedded (WES))