+5v NOT SHOWING IN BIOS.

I have a cheap power supply which came with the cabinet.Yesterday I ran everest diagnostic software to know about my ram and cpu fsb.To my shock when I checked the voltage,only +3v and +12v are visible.Thought maybe a software mistake.Checked again with sisoftware sandra lite.Same results.Here are the results

SISOFTWARE SANDRA LITE:
Voltage Sensor(s)
CPU DC Line : 1.25V
Aux DC Line : 2.59V
+3.3V DC Line : 3.12V
+12V DC Line : 11.36V
-12V DC Line : -1.17V
-5V DC Line : 0.53V
Battery DC Line : 3.14V

EVEREST:
Voltage Values:
CPU Core 1.26 V
+2.5 V 2.58 V
+3.3 V 3.10 V
+12 V 11.84 V
VBAT Battery 3.14 V

Panicking I restarted the computer and checked the bios.To my worst fear only +3v and +12v were visible,no +5v.The computer is working ok,though have had only 2 crashes in the last 2 months(thought they were a result of heat).
Could someone tell me is this going to harmful for my computer.My computer's low end and has been running perfectly fine.No error in the event manager.Any help would be really appreciated.Thank you.


MY COMPUTER SPEC:
DUAL CORE 2.8
512MB RAM
SAMSUNG 80GB
SEAGATE 500GB
OPERATING SYSTEM:XP SP3

Thank you for replying.Is there any other way to check the +5v(noob when it comes to handling electrical tools and parts).Could anybody tell me,supposedly if the +5v not working what problems can I face.Would the computer even start if the +5v was not working.Please shed some light

Motherboards no longer use the 5v line themsleves, all voltages are supplied from an onboard switching supply on the 12 volt line. -5 is also not used, notice the wonky ".53" for the -5v line in Sandra. It WOULD be an idea to check the red wire on the molexes connected to the hard drives with a multimeter to make sure the voltage is close. This is easy stuff to do.