1GB Ram wont work on my laptop!!! please help me!!!

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i bought a stick of ram a few months back..and it wasnt working. ive posted on some forums but none of them were helpful..so hopefully this site can. i have a fujitsu n5010 laptop and it can hold 2 gigs of ram. when i bought it, it came with 512mb (2x256) pc2700 ddr333. its from micron technology. i knew that cause i checked the specs using cpuid. i decided to upgrade my ram to a gig so i bought 1gig of ram from frys electronics. same specs everything..or at least i think it is..its a corsair 1gb sodimm and its the valueselect one. i put it in just by itself without the other 256 and it worked for a while..then when i turn on my laptop it doesnt work and it gives me a beep like 1-3-4-3 I THINK?? im not sure..but yea it meant something about 512k test? the laptop goes on but screen is just black. and people told me to do that (512k test?) but i dont know how to heck to do that! whats wrong? what can i do? i even took it back and they said nothing was wrong with it and that it works fine with the factory installed memory brand that i bought it with. you think i have to have 2 sticks of 1gb for it to work??? i tried all combinations. first slot only second slot only. mixed the brands and memory. (1gb and 256mb) still nothing..i even asked in the forums and they said that corsair was one fo the best memory brands and kingston kingstone whatever it is..was the other one. is patriot good? cause thats the most expensive one next to corsiar the one i got thats left at the store..i even check corsairs site. and they have my laptop and memory everytyhing..and it doesnt work

and what if i cant adjust the timings on my ram on my bios cause i cant..i put just the one stick in in slot 1 didnt work..same thing for slot 2 didnt work..and mixing it with one of the micron tech 256 making it 1.2gb ram...didnt work. so will it work if i use another brand you think? and whats that 512k test that i also heard from people saying about? cause im getting those beeps..i think i have phoenix bios? i get the beeps 1-3-4-3???? when the 1 stick of corsair memory wont work. awww..i really want this one stick...so i can play games faster..lol how about getting another stick of 1 gb? people keep saying corsair is like one of the best but somehow its not working with my fujitsu n5010... stupid valueselect cheap crap..should of gotten the more expensive..and stupid corsair saying they have memory for my laptop even did the mem config tool too at their site... =( i want 1 gig on my laptop at least! =(