Computer wont start up,keyboard flashes

[sunzzofman]

im putting together a pc for a friend useing all my spare parts that iv slowly replaced over time but iv hit a snag.when i turn the pc on the power light lights up blue,the motherboard led lights up and all the fans are spinning etc,yet my moniter doesnt pick up a signal,and my keyboard(saitek eclipse) keeps on flashing over and over.iv checked everything in the pc and carnt find anything wrong or missing etc.it has a external graphics card to.what am i doing wrong? also the case im useing doesnt have a system connectors speaker,so im not sure if theres any beep error codes etc.iv also checked the system connectors and the hd led on the pc case doesnt light up,yet its in the correct way,tried it with 2 different hardrives and still the same problem. pleasssse help thanks in advance

 

[cmichael138]

Please list your parts. Could be a compatibility issue

 

[sunzzofman]

ah got it working now.all i did was removed the 2 1gb sticks of ram i had in,and put them in the other 2 slots nearer the motherboard and it turned on and worked fine,so i thought il put them back into the other 2 slots and if it doesnt work il know its them 2 slots.but it did work lol :S im confused now as i want to know what causes it for future reference

psu 500w
motherboard asus m3a green
gfx card geforce 8600gt 512mb pci e
ram : 1 gb ddr2 800 mhz x 2

 

[Raiddinn]

Broken RAM slots can certainly cause such problems.

If you can switch them back and forth and they consistently don't work in 2 slots and do work in a different 2 slots, its probably a broken slot problem.

If you don't get consistent results after switching slots over and over, its probably the fact that they are or aren't being pushed in hard enough. If you just barely stick it in the slot (even if the clips latch onto the RAM) then the motherboard wouldn't be able to read the whole stick. That is also a common cause of restart loops.

 

[sunzzofman]

oo ok i get ya,but surley if one sticks in ones not it should just run on one stick? surley both sticks wasnt pushed in proberly? thanks for youre replys btw

 

[Raiddinn]

If you had a computer with 20 slots and you had 20 sticks in it and one of them was too much out of the slot to be readable then as likely as not you couldn't get the computer to boot at all.

Computers are trained to detect problems with themselves and to take certain actions when problems are detected. Restarting over and over is a response computers are trained to do in certain situations.

Not having every stick fully usable is one of those situations.