Windows XP Pro Keeps Rebooting Randomly

Hello my name is Autumn - My computer keeps rebooting randomly by itself and I don't know what to do. I hope you can help me. I have pasted my computer specs and 3 blue screen messages into this posting.
I would be so grateful for any help you could give me

Operating System Microsoft Windows XP Professional
OS Service Pack Service Pack 3
DirectX 4.09.00.0904 (DirectX 9.0c)

Motherboard:
CPU Type AMD Athlon 64, 2000 MHz (10 x 200) 3200+
Motherboard Name MSI K8N Neo4 Platinum (MS-7125) (4 PCI, 1 PCI-E x1, 1 PCI-E x4, 1 PCI-E x16, 4 DDR DIMM, Audio, Dual Gigabit LAN, IEEE-1394)
Motherboard Chipset nVIDIA nForce4 Ultra, AMD Hammer
System Memory 2048 MB (PC3200 DDR SDRAM)
BIOS Type Award (01/12/05)
Communication Port Communications Port (COM1)
Communication Port Printer Port (LPT1)

Display:
Video Adapter RADEON X300/X550 Series Secondary (128 MB)
Video Adapter RADEON X300/X550 Series (128 MB)
3D Accelerator ATI Radeon X300 (RV370)
Monitor Acer AL1715 [NoDB] (ETL2102135)

Multimedia:
Audio Adapter Creative SB0350 Audigy 2 ZS Sound Card

Storage:
IDE Controller Standard Dual Channel PCI IDE Controller
IDE Controller Standard Dual Channel PCI IDE Controller
IDE Controller Standard Dual Channel PCI IDE Controller
SCSI/RAID Controller D344PRT SCSI Controller
Floppy Drive Floppy disk drive
Disk Drive ST3160212A (149 GB, IDE)
Optical Drive Generic DVD-ROM SCSI CdRom Device
Optical Drive PIONEER DVD-RW DVR-108 (DVD+R9:4x, DVD+RW:16x/4x, DVD-RW:16x/4x, DVD-ROM:16x, CD:32x/24x/40x DVD+RW/DVD-RW)
SMART Hard Disks Status OK

Partitions:
C: (NTFS) 152625 MB (130409 MB free)

Input:
Keyboard Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
Mouse PS/2 Compatible Mouse

Network:
Network Adapter SMC2802W 2.4GHz 54 Mbps Wireless PCI Adapter (192.168.0.102)

Peripherals:
Printer Canon i350
Printer Microsoft Office Document Image Writer
Printer Microsoft XPS Document Writer
USB1 Controller nVIDIA MCP04 - OHCI USB Controller
USB2 Controller nVIDIA MCP04 - EHCI USB 2.0 Controller
USB Device hp scanjet 3600 series




Dump File : Mini060611-03.dmp
Crash Time : 6/6/2011 6:47:12 PM
Bug Check String : IRQL_NOT_LESS_OR_EQUAL
Bug Check Code : 0x1000000a
Parameter 1 : 0x00001000
Parameter 2 : 0x00000002
Parameter 3 : 0x00000001
Parameter 4 : 0x806d524d
Caused By Driver : hal.dll
Caused By Address : hal.dll+424d
File Description : Hardware Abstraction Layer DLL
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 5.1.2600.5512 (xpsp.080413-2111)
Processor : 32-bit
Crash Address : hal.dll+424d
Stack Address 1 : hal.dll+482a
Stack Address 2 : hal.dll+4b78
Stack Address 3 : PCIIDEX.SYS+ddb
Computer Name :
Full Path : C:\WINDOWS\Minidump\Mini060611-03.dmp
Processors Count : 1
Major Version : 15
Minor Version : 2600
Dump File Size : 90,112

Dump File : Mini060611-02.dmp
Crash Time : 6/6/2011 6:18:54 PM
Bug Check String : IRQL_NOT_LESS_OR_EQUAL
Bug Check Code : 0x1000000a
Parameter 1 : 0x5c2a9025
Parameter 2 : 0x00000002
Parameter 3 : 0x00000001
Parameter 4 : 0x8051221b
Caused By Driver : ntoskrnl.exe
Caused By Address : ntoskrnl.exe+3b21b
File Description : NT Kernel & System
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 5.1.2600.6055 (xpsp_sp3_gdr.101209-1647)
Processor : 32-bit
Crash Address : ntoskrnl.exe+3b21b
Stack Address 1 : ntoskrnl.exe+3c2af
Stack Address 2 : ntoskrnl.exe+3c3fa
Stack Address 3 : ntoskrnl.exe+46335
Computer Name :
Full Path : C:\WINDOWS\Minidump\Mini060611-02.dmp
Processors Count : 1
Major Version : 15
Minor Version : 2600
Dump File Size : 90,112

Dump File : Mini060611-01.dmp
Crash Time : 6/6/2011 5:58:51 PM
Bug Check String : KERNEL_MODE_EXCEPTION_NOT_HANDLED
Bug Check Code : 0x1000008e
Parameter 1 : 0xc0000005
Parameter 2 : 0xbf0f27c6
Parameter 3 : 0xad5bcb68
Parameter 4 : 0x00000000
Caused By Driver : ati3duag.dll
Caused By Address : ati3duag.dll+157c6
File Description : ati3duag.dll
Product Name : ATI Technologies Inc. Radeon DirectX Universal Driver
Company : ATI Technologies Inc.
File Version : 6.14.10.0419
Processor : 32-bit
Crash Address : ati3duag.dll+157c6
Stack Address 1 :
Stack Address 2 :
Stack Address 3 :
Computer Name :
Full Path : C:\WINDOWS\Minidump\Mini060611-01.dmp
Processors Count : 1
Major Version : 15
Minor Version : 2600
Dump File Size : 90,112