Computer will not work with 2 sticks of memory

if you put stick 1 in slot 1 and stick 2 in slot 2 it doesnt boot, correct?  Have you tried Stick 2 in slot 1 and stick 1 in slot 2 as well as just putting 1 stick in the second slot and leaving the first slot open.

yes tried all that... only thing that works is one stick in slot 1...

Sounds like slot 1 has failed. Have you visually inspected that slot for damage, etc?

You mean slot 2 has failed.... since memory in slot one works.... if I am reading right.

Sometimes a bad memory stick may short out the memory slot. Since this system came back from repair... it is possible during the repair process the technician found a bad stick of memory and once he remove the memory from that slot the system booted up. He should have informed or tested to see if that slot that the memory was removed from was bad. Static electricity could also have damaged this slot or it is possible that the slot itself may be visibly damaged

Will visually inspect on Thursday when I get back

was the 4 GB original the same sticks as the replacement ones?
does it still work with those 4 GB ?

I have an Acer desktop (939) with four slots, and the 2nd is bad. No matter what I do it won't work. I had the same problem. It came with 2x500MB sticks and tried to put in 4 1GB chips...
Thought 1 stick was bad but through trial and error discovered that slot 2 was bad.
Nothing to be done about it.

If it came back from repair with all 4GB installed and working, it's going to come down to the shop saying you have done something to make it not work.  Are you familiar with how memory is properly installed?  Perhaps the second slot doesn't "click" in place?  Is it identical to the first slot, with locks?  If the memory is not firmly seated and lock engaged, it won't work.

did you use any ESD protection?

If you got it back with 4GB of memory, then the slot was fine when you got it back...When you say that you swapped memory around...if you did not use and grounding equipment (like an anti-static strap, or held onto the tower with one hand at all times, then you may have transferred static electricity and fried the memory slot.  You can try to reset BIOS by either using the jumper on the motherboard, or removing the little battery on the motherboard over night with the computer unplugged...then give it a whirl.

you can test all slots with the 1 working stick in each slot

it was the slot... the MB was bad...

I've requested that this question be closed as follows:

Accepted answer: 0 points for ambantin's comment #a38580074

for the following reason:

bad board