bug#8157: emacs 23.1 hung on windows 7

[Tony An]

Emacs version: GNU Emacs 23.1.1 (i386-mingw-nt6.1.7600) of 2009-07-29 on 
SOFT-MJASON

When I was editing a .tex file, it contantly hung at me on windows 7:

Description:
  A problem caused this program to stop interacting with Windows.

Problem signature:
  Problem Event Name:   AppHangB1
  Application Name:     emacs.exe
  Application Version:  23.1.0.0
  Application Timestamp:        4a71276f
  Hang Signature:       89ef
  Hang Type:    6144
  OS Version:   6.1.7600.2.0.0.256.4
  Locale ID:    1033
  Additional Hang Signature 1:  89efb76b03c95ee690061483225efa8f
  Additional Hang Signature 2:  dd94
  Additional Hang Signature 3:  dd944310c3239a2fb4f3c2800c14dcd5
  Additional Hang Signature 4:  89ef
  Additional Hang Signature 5:  89efb76b03c95ee690061483225efa8f
  Additional Hang Signature 6:  dd94
  Additional Hang Signature 7:  dd944310c3239a2fb4f3c2800c14dcd5