Computer Freezes Frequently

Frequently (at least a couple times a day) my computer screen freezes and emits a terrible scraping if the audio is plugged into speakers until I manually power down. When I reboot, I get the following error in the log:

"The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly."

Name: Microsoft-Windows-Kernel-Power

Guide: {331C3B3A-2005-44C2-AC5E-77220C37D6B4}

EventID 41

Version 2

Level 1

Task 63

Opcode 0

Keywords 0x8000000000000002

TimeCreated

[ SystemTime] 2010-01-10T06:39:47.187500000Z

EventRecordID 21377

Correlation

Execution

[ ProcessID] 4

[ ThreadID] 8

Channel System

Computer Desktop-PC

Security

[ UserID] S-1-5-18

EventData

BugcheckCode 0

BugcheckParameter1 0x0

BugcheckParameter2 0x0

BugcheckParameter3 0x0

BugcheckParameter4 0x0

SleepInProgress false

PowerButtonTimestamp 0

I also get the following:

System

Provider

[ Name] EventLog

EventID 6008

[ Qualifiers] 32768

Level 2

Task 0

Keywords 0x80000000000000

TimeCreated

[ SystemTime] 2010-01-10T06:40:11.000000000Z

EventRecordID 21373

Channel System

Computer Desktop-PC

Security

EventData

1:10:52 AM

‎1/‎10/‎2010

7042

DA07010000000A0001000A003400EE02DA07010000000A0006000A003400EE02600900003C000000010000006009000000000000B00400000100000000000000

Binary data:

In Words

0000: 000107DA 000A0000 000A0001 02EE0034

0008: 000107DA 000A0000 000A0006 02EE0034

0010: 00000960 0000003C 00000001 00000960

0018: 00000000 000004B0 00000001 00000000

In Bytes

0000: DA 07 01 00 00 00 0A 00 Ú.......

0008: 01 00 0A 00 34 00 EE 02 ....4.î.

0010: DA 07 01 00 00 00 0A 00 Ú.......

0018: 06 00 0A 00 34 00 EE 02 ....4.î.

0020: 60 09 00 00 3C 00 00 00 `...