weird cd-drive behaviour

[kaushal <kaushal@rocsys.com>]

Hello all,
	My cd-drive is behaving weirdly when I insert a cd-rom in it.It reacts
in any of the following ways:
	System hangs
	Display garbles + system hangs
	System turns off immediately 
	Runs normally!
Also sometimes the system doesn't turn on when  I press the power/reset
button.Then I will off and on the UPS then the system turns on before I
press the power button.

Sometimes the system turns on upon pressing the power button,hardisk 
activity seems to happen ,but nothing not-even "POST "messages come up
and the CPU fan keeps rotating.the leds(power+hdd)continue glowing.

Another strange thing that I notice is that :When the system boots up
sometimes the modem(serial) has two leds glowing and sometimes only one
led glowing(I guess 1 led means proper initialization).These leds are
control signals for the modem.CT,...and not power / anything else(venus
modem)

Im unable to figure out the faulty hardware section.But once when I
tried to copy some content from the cd to hdd in linux I recv. the
following error messages:

hdd:command error:status=0x51 {Drive Ready SeekComplete Error}
hdd:command error:error=0x54

After those error messages the system got stuck.Then I restarted the m/c
and the /var/log/messages showed the following two messages at two
different times:

kernel:hda:hda:dma_intr:status=0x51 {Drive Ready SeekComplete Error}
kernel:hda:dma_intr:error=0x84 {Drive StatusError Bad CRC}

I guess there is some system initialization problem.
 or DMA problem(last 2 messages}

Please help me in this aspect.Any way to debug further and diagnose and
corner the faulty section?

Thanks in advance.

kaushal.