I have upgraded my COMPAQ C770TU (C700 series) Laptop with a new 1Gb 667MHz DDR2 from Transcend. After installing the new RAM module (I now have two RAMs) my laptop randomly refuses to boot. No BIOS messages, no HDD activity nothing. The system starts up, spins up the CPU fan as normal, then shutdown the fan and waits. After some time the CPU heats up and the fan starts to spin again. The weird thing is that this happens only randomly.
One time, the problem persisted even after I removed the new module. (This only happened once). Afterwards without the new module everything was OK.
Then I installed the new module again, the laptop failed to boot, but on the second attempt it booted and windows and BIOS has found 2Gb of RAM (1Gb x 2).
I am afraid, the problem will persist. Can someone please help.
I have found that, it will fail to boot normally. Now if I press any of the system keys (like F1 for system info F10 for BIOS) or any such keys, it will lemme boot. and everything works normally. I will have the whole 2Gb of RAM. But if I don't press any key when I power it up, it will get stuck. I have added DDR2 667MHz.
It may not be the correct type for your laptop; modules can be extremely specific. I would look yours up but I don't have time right now. Remove them both and compare markings, they should be identical, if they are not, return the new one and exchange it. It isi also very possible that you have a bad module. Either way, i would return it for an exchange.