Kernel Panic

One of the important server, frequently kernel panic.
Every few hours, after restart..
Will not responding and kernel panic again..
This server CD-ROM already defected..
I hardly can linux repair the kernel..

Things I can do also limited.. due to the not functioning CD-ROM..
But sometimes when i reboot this server..
It will have 1-3-2 beep sound which indicate the memory are not installed properly..
refer to here..
Another symptom on this server Dell Poweredge 1650..
was the BIOS screen is hang hang..

What I suspect:
1. Board defect.. which cause the BIOS hang..
2. Hard Disk defect.. due to the irq timeout..

What I had try to fixed this problem:
1. Remove the RAM.. and test the RAM pair at Bank 1.. This one can know which RAM is defected. And found out one of the 512MB RAM is defected which cause the BIOS screen hang hang.

2. Change the CD-ROM from other server. Try do linux repair.. Found out the message indicate the hda irq is timeout before change the CD-ROM.

In the end, after all the test.. Found out the main cause for the Kernel Panic was
1. 1 of the RAM is defect..
2. CD-ROM (hda) is defect..

After i remove the RAM and change the CD-ROM.. Everything is working fine..