No error shown on Screen

[kwfine]

Hi all,

I have got an old PC (5 years old).
Its motherboard has 4 RAM Slots, but only 2 of them are used, 256MB each.
I purchased another 256MB RAM from a second-hand market yesterday.
But I found that the power light of my PC's monitor just kept flashing immediately
after I inserted this new RAM into the RAM Slot, and
the monitor couldn't be powered on, I couldn't see anything.
Later I found that the problem was caused by this RAM, which
must have been damaged beforehand.
Although the problem got fixed finally, I was wondering why
my PC's monitor couldn't be powered on or display anything on screen,
because the other two RAMs in the RAM slot are fine.
I am not sure if it is something related to the PC's BIOS?
I dont know why the BIOS did not show me any error messages
related to defective or damaged RAM?

Any ideas?

[hellnoire]

Your computer looks to run off all the ram you have, because it thinks all of it is good. While this isn't always the case, if it finds any bum/bad ram, you're not going to be able to go anywhere because the BIOS is hardcoded to check and do a quick test of your ram first.

[kimlanvn]

Are your old ram and new ram same bus ? Your 4 RAM must same bus (ex: 133, 667, 800)
Sorry for my English !