Windows 7: Windows 7 Freeze Up

Has any one experienced a total freeze up with windows 7 requiring a shut down and reboot? Ctrl+Alt+Del will not invoke the Task Manager. I mean a total freeze up.

This is my current machine specs
OS Name Microsoft! Windows 7 Home Premium
System Name
System Manufacturer Dell Inc.
System Model Inspiron 546S
System Type x64-based PC
Processor AMD Phenom(tm) 3450e Triple-Core Processor
BIOS Version/Date Dell Inc. A05, 5/11/2009
SMBIOS Version 2.5
Installed Physical Memory (RAM) 8.00 GB
Total Physical Memory 7.75 GB
Available Physical Memory 5.38 GB
Total Virtual Memory 15.7 GB

First to find what is happening go into event viewer (eventvwr in search) go t to the windows logs>application tab. You want to look for critical errors (they have red in the left hand column) that sya app ahng, app crash, etc. when the find then please note the event ID and source code and relay that to us for analysis.

I see several as in a lot of Event ID 218 -- Media Manager Indexer
Only 1 1002 Application Hang
a few 10 WMI
5 59 SidebySide