Mac shutting down on its own

i was using the computer just now and suddenly a black shade came over the screen and i was informed i had to restart the computer,this had happened one other time in my school,when i turned on the mac again i had this information


panic(cpu 0 caller 0x001A49CB): Unresolved kernel trap (CPU 0, Type 14=page fault), registers:
CR0: 0x8001003b, CR2: 0x0000003c, CR3: 0x01261000, CR4: 0x000006e0
EAX: 0x00000000, EBX: 0x00000000, ECX: 0x00000000, EDX: 0x00000000
CR2: 0x0000003c, EBP: 0x258c38a8, ESI: 0x000005a8, EDI: 0x374ee858
EFL: 0x00010202, EIP: 0x005b3367, CS: 0x00000008, DS: 0x307a0010

Backtrace, Format - Frame : Return Address (4 potential args on stack)
0x258c3678 : 0x128d0d (0x3cc65c 0x258c369c 0x131f95 0x0)
0x258c36b8 : 0x1a49cb (0x3d2a94 0x0 0xe 0x3d22b8)
0x258c37c8 : 0x19b3a4 (0x258c37e0 0x0 0x258c3808 0x14009d)
0x258c38a8 : 0x5ada4c (0x0 0x258c3b2c 0x0 0x0)
0x258c3b58 : 0x5ae17f (0x258c3c34 0x3e8 0x1 0x1a3736)
0x258c3b98 : 0x372d52 (0x76e75a0 0x72db864 0x0 0x258c3c34)
0x258c3be8 : 0x364211 (0x72db864 0x0 0x258c3c34 0x0)
0x258c3c28 : 0x239483 (0x72db8a8 0x3758b000 0x1 0x6f00a8c0)
0x258c3e08 : 0x22f8b2 (0x3758b000 0x14 0x14 0x6)
0x258c3e48 : 0x231313 (0x3758b000 0x14 0x6 0x0)
0x258c3f58 : 0x21ea88 (0x3758b000 0x3758b000 0x44707c 0x1a3736)
0x258c3f98 : 0x20529e (0x463ec04 0x3758b000 0x374ee816 0x1)
0x258c3fc8 : 0x19b21c (0x0 0x0 0x19e0b5 0x3f5e2dc) Backtrace terminated-invalid frame pointer 0x0
Kernel loadable modules in backtrace (with dependencies):
com.symantec.kext.ips(1.2f28)@0x5aa000
dependency: com.symantec.kext.internetSecurity(1.1f10)@0x5a1000

Kernel version:
Darwin Kernel Version 8.11.1: Wed Oct 10 18:23:28 PDT 2007; root:xnu-792.25.20~1/RELEASE_I386

Model: MacBookPro3,1, BootROM MBP31.0070.B07, 2 processors, Intel Core 2 Duo, 2.4 GHz, 2 GB
Graphics: GeForce 8600M GT, GeForce 8600M GT, PCIe, 256 MB
Memory Module: BANK 0/DIMM0, 1 GB, DDR2 SDRAM, 667 MHz
Memory Module: BANK 1/DIMM1, 1 GB, DDR2 SDRAM, 667 MHz
AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x87), 1.3.5
Bluetooth: Version 1.9.5f4, 2 service, 1 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Network Service: Ethernet Adaptor (en2), Ethernet, en2
Network Service: Ethernet Adaptor (en3), Ethernet, en3
PCI Card: pci168c,24, sppci_othernetwork, PCI Slot 5
Serial ATA Device: ST9160823AS, 149.05 GB
Parallel ATA Device: MATSHITADVD-R UJ-857E
USB Device: Built-in iSight, Apple Inc., Up to 480 Mb/sec, 500 mA
USB Device: External HDD, Western Digital, Up to 480 Mb/sec, 500 mA
USB Device: Apple Internal Keyboard / Trackpad, Apple Computer, Up to 12 Mb/sec, 500 mA
USB Device: IR Receiver, Apple Computer, Inc., Up to 1.5 Mb/sec, 500 mA
USB Device: Bluetooth USB Host Controller, Apple, Inc., Up to 12 Mb/sec, 500 mA




I suppose that was a kernel pannick?i dont really know what that is,but why would you think this happened?could i have been hacked or what?

Some info to start with.
http://www.thexlab.com/faqs/kernelpanics.html
http://docs.info.apple.com/article.html?artnum=106227