Various Application Errors due to faulting module ntdll.dll

Hello,

First off, I run Vista Home Premium 32-bit. In the past several months I've
started receiving error messages when my computer recovers from Sleep Mode. I
don't remember when it started and I can't roll back that far. Various
programs - explorer.exe, wmplayer.exe, outlook.exe and others - "stop
working" and most of them indicate ntdll.dll as the faulting module (see
event viewer logs included below). Please help!
----------
Log Name: Application
Source: Application Error
Date: 7/22/2008 11:20:48 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: ...
Description:
Faulting application Explorer.EXE, version 6.0.6000.16549, time stamp
0x46d230c5, faulting module ntdll.dll, version 6.0.6000.16386, time stamp
0x4549bdc9, exception code 0xc0000374, fault offset 0x000af1c9, process id
0x824, application start time 0x01c8eb384724f9be.
----------
Log Name: Application
Source: Application Error
Date: 8/16/2008 12:27:11 PM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: ...
Description:
Faulting application wmplayer.exe, version 11.0.6001.7000, time stamp
0x47919356, faulting module ntdll.dll, version 6.0.6001.18000, time stamp
0x4791a7a6, exception code 0xc0000005, fault offset 0x0003d13a, process id
0x1510, application start time 0x01c8ffc54e67ba00.
----------
Log Name: Application
Source: Application Error
Date: 8/9/2008 8:49:01 AM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: ...
Description:
Faulting application OUTLOOK.EXE, version 11.0.5510.0, time stamp
0x3f1380f0, faulting module ntdll.dll, version 6.0.6001.18000, time stamp
0x4791a7a6, exception code 0xc0000005, fault offset 0x000658c8, process id
0x1538, application start time 0x01c8fa26a95e4d10.