RAM Upgrade problem

[Leon_Mokomaki]

So at the moment i have 512mb DDR-DIMM CL2.5 RAM. ( Dont laugh  )
I just got 2x 1gb DDR, 400, CL3 RAM

I have 3 slots in my motherboard. I have a BANK1          BANK 0
                                                          dimm2          dimm1                                  
                                                          dimm3                                                        
                                                                                                                                                                                     Dimm 2 and Dimm1 are PURPLE and Dimm3 is Black                                                                                                                                                                                                                      

And if i put all the RAM in ( 2.5gb) My computer will start but it will just keep rebooting after the windows XP loading screen.
ive tried putting only both the 1gb (2gb) RAM in BANK1 and also 1 of the 1gb ram in Bank1 and the other one in Bank0...

Only way it seems to work is like i have them now (. 512mb in BANK1 and one of the 1gb in BANK0)
Can it be cause of my crap CPU ( AMD Sempron 2400+ 1666ghz) OR my Power supply is too crap? Or what?
Please help

[Bilbo]

Does it work when you replace the 512Mb stick with 1024Mb one? If it does, I guess either one of the extra ones are broken.

[Leon_Mokomaki]

if i put 1 both 1gb in purple slots pc doesnt start

[Fuzzy]

Could be a faulty RAM Stick or RAM Slot, not sure though, but try running a memory test with Everest.

[Todor]

Try using just the 2x1 gig sticks. Sometimes motherboards dont really like different size and frequency RAM sticks

[Bilbo]

if i put 1 both 1gb in purple slots pc doesnt start

Replace the original 1x512Mb with 1x1024Mb, and tell if it works. If it didn't work, your RAM stick is broken.

[el_boricua56]

What motherboard model you have?