１ Ubuntuソフトウェアセンターからインストールしました
２ 存在していません。

lm-sensorsはインストールしたはずです。

ちなみに
＊＊＊＊＊@＊＊＊＊＊＊-desktop:~$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +30.0°C  (crit = +127.0°C) 

としか表示されません・・・

Ubuntuは新規インストールです。
やっぱり
＊＊＊＊＊@＊＊＊＊＊＊-desktop:~$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +30.0°C  (crit = +127.0°C)
とだけ表示されます。

sensors-appletでもやっぱり30℃としか表示されません。

リンクのとおりやったんですが、

＊＊＊＊＊@＊＊＊＊＊＊-desktop:~$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +30.0°C  (crit = +127.0°C)

としか表示されません。

*****@*****-desktop:~$ sudo sensors-detect
[sudo] password for *****:
# sensors-detect revision 5818 (2010-01-18 17:22:07 +0100)

This program will help you determine which kernel modules you need
to load to use lm_sensors most effectively. It is generally safe
and recommended to accept the default answers to all questions,
unless you know what you're doing.

Some south bridges, CPUs or memory controllers contain embedded sensors.
Do you want to scan for them? This is totally safe. (YES/no): YES
Silicon Integrated Systems SIS5595...                       No
VIA VT82C686 Integrated Sensors...                          No
VIA VT8231 Integrated Sensors...                            No
AMD K8 thermal sensors...                                   No
AMD Family 10h thermal sensors...                           No
AMD Family 11h thermal sensors...                           No
Intel Core family thermal sensor...                         No
Intel Atom thermal sensor...                                No
Intel AMB FB-DIMM thermal sensor...                         No
VIA C7 thermal sensor...                                    No
VIA Nano thermal sensor...                                  No

Some Super I/O chips contain embedded sensors. We have to write to
standard I/O ports to probe them. This is usually safe.
Do you want to scan for Super I/O sensors? (YES/no): YES
Probing for Super-I/O at 0x2e/0x2f
Trying family `National Semiconductor'...                   No
Trying family `SMSC'...                                     No
Trying family `VIA/Winbond/Nuvoton/Fintek'...               No
Trying family `ITE'...                                      No
Probing for Super-I/O at 0x4e/0x4f
Trying family `National Semiconductor'...                   No
Trying family `SMSC'...                                     No
Trying family `VIA/Winbond/Nuvoton/Fintek'...               Yes
Found `Fintek F71882FG/F71883FG Super IO Sensors'           Success!
    (address 0x295, driver `f71882fg')

Some systems (mainly servers) implement IPMI, a set of common interfaces
through which system health data may be retrieved, amongst other things.
We first try to get the information from SMBIOS. If we don't find it
there, we have to read from arbitrary I/O ports to probe for such
interfaces. This is normally safe. Do you want to scan for IPMI
interfaces? (YES/no): YES
Probing for `IPMI BMC KCS' at 0xca0...                      No
Probing for `IPMI BMC SMIC' at 0xca8...                     No

Some hardware monitoring chips are accessible through the ISA I/O ports.
We have to write to arbitrary I/O ports to probe them. This is usually
safe though. Yes, you do have ISA I/O ports even if you do not have any
ISA slots! Do you want to scan the ISA I/O ports? (yes/NO): yes
Probing for `National Semiconductor LM78' at 0x290...       No
Probing for `National Semiconductor LM79' at 0x290...       No
Probing for `Winbond W83781D' at 0x290...                   No
Probing for `Winbond W83782D' at 0x290...                   No

Lastly, we can probe the I2C/SMBus adapters for connected hardware
monitoring devices. This is the most risky part, and while it works
reasonably well on most systems, it has been reported to cause trouble
on some systems.
Do you want to probe the I2C/SMBus adapters now? (YES/no): YES
Using driver `i2c-i801' for device 0000:00:1f.3: Intel 82801H ICH8
Module i2c-i801 loaded successfully.
Module i2c-dev loaded successfully.

Next adapter: intel drm CRTDDC_A (i2c-0)
Do you want to scan it? (YES/no/selectively): YES
Client found at address 0x50
Probing for `Analog Devices ADM1033'...                     No
Probing for `Analog Devices ADM1034'...                     No
Probing for `SPD EEPROM'...                                 No
Probing for `EDID EEPROM'...                                Yes
    (confidence 8, not a hardware monitoring chip)

Next adapter: SMBus I801 adapter at 0500 (i2c-1)
Do you want to scan it? (yes/NO/selectively): yes
Client found at address 0x2f
Seems to be a 1-register-only device, skipping.
Client found at address 0x50
Probing for `Analog Devices ADM1033'...                     No
Probing for `Analog Devices ADM1034'...                     No
Probing for `SPD EEPROM'...                                 Yes
    (confidence 8, not a hardware monitoring chip)
Probing for `EDID EEPROM'...                                No

Now follows a summary of the probes I have just done.
Just press ENTER to continue:

Driver `f71882fg':
  * ISA bus, address 0x295
    Chip `Fintek F71882FG/F71883FG Super IO Sensors' (confidence: 9)

To load everything that is needed, add this to /etc/modules:
#----cut here----
# Chip drivers
f71882fg
#----cut here----
If you have some drivers built into your kernel, the list above will
contain too many modules. Skip the appropriate ones!

Do you want to add these lines automatically to /etc/modules? (yes/NO)yes
Successful!

Monitoring programs won't work until the needed modules are
loaded. You may want to run '/etc/init.d/module-init-tools start'
to load them.

Unloading i2c-dev... OK
Unloading i2c-i801... OK

*****@*****-desktop:~$ sudo /etc/init.d/module-init-tools start
[sudo] password for *****: 
Rather than invoking init scripts through /etc/init.d, use the service(8)
utility, e.g. service module-init-tools start

Since the script you are attempting to invoke has been converted to an
Upstart job, you may also use the start(8) utility, e.g. start module-init-tools
module-init-tools stop/waiting

と表示され、再起動してみるものの、やっぱり

＊＊＊＊＊@＊＊＊＊＊＊-desktop:~$ sensors
acpitz-virtual-0
Adapter: Virtual device
temp1:       +30.0°C  (crit = +127.0°C)

としか表示されません

BIOSで見てみると、起動時は30℃ぐらいですが放置しておくと40℃から45℃ぐらいまで上がります。
30分ほどCPUに負荷をかけてみても30℃から一向に変わりません・・・