sony vaio CPU overheats

I have a sony vaio C1Z that I installed ubuntu 10.10 on. I'm using the 32 bit ubuntu 10.10 standard desktop edition.

The CPU temperature starts out at about 40 C and slowly creeps its way up to 70 C. After 72 C the PC shuts down, I assume some safety system on the motherboard is kicking in.
On the Windows XP partition the fans become louder as the CPU temperature rises. The fans do not change speed at any point when ubuntu is running so I suspect this is the cause.
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AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC262 Analog [ALC262 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC262 Analog [ALC262 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: stuart 1390 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xd2300000 irq 46'
   Mixer name : 'Realtek ALC262'
   Components : 'HDA:10ec0262,104d1500,00100100 HDA:14f12c06,104d1700,00100000'
   Controls : 18
   Simple ctrls : 11
DistroRelease: Ubuntu 10.10
HibernationDevice: RESUME=UUID=9192da4b-f4ed-429b-b9b5-cfba5065c45d
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
MachineType: Sony Corporation VGN-C1Z_B
NonfreeKernelModules: nvidia
Package: linux (not installed)
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.35-22-generic root=UUID=ddc897c0-70d5-4ab7-add8-052c6e771e5e ro quiet splash
ProcEnviron:
 PATH=(custom, user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.35-22.35-generic 2.6.35.4
Regression: Yes
RelatedPackageVersions: linux-firmware 1.38
Reproducible: Yes
Tags: maverick kernel-uncat regression-release needs-upstream-testing
Uname: Linux 2.6.35-22-generic i686
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare
dmi.bios.date: 09/16/2006
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: R0030J4
dmi.board.asset.tag: N/A
dmi.board.name: VAIO
dmi.board.vendor: Sony Corporation
dmi.board.version: N/A
dmi.chassis.asset.tag: N/A
dmi.chassis.type: 10
dmi.chassis.vendor: Sony Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrR0030J4:bd09/16/2006:svnSonyCorporation:pnVGN-C1Z_B:pvrC3LN4F1X:rvnSonyCorporation:rnVAIO:rvrN/A:cvnSonyCorporation:ct10:cvrN/A:
dmi.product.name: VGN-C1Z_B
dmi.product.version: C3LN4F1X
dmi.sys.vendor: Sony Corporation