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My laptop previously had 2 slots of RAM ( 1x1Gb , 1x2GB , both were clocked at 1066mhz) and it was working on windows 7 x86 OS. I Upgraded the ram with ( 2x4GB clcoked at 1333mhz). Bios displayed 8192MB of memory and windows was working ok but (only 2.99GB of ram from 8gb was avabile). So i decided to switch to an x64 system to be able to use all the amount of memory. But the laptop wasnt able to install any os (windows 7 x64 or windows 8 x64) so i placed the 3gb of ram instead of 8gb. Then i succesfully instaled an x64 os (windows 8). After than i placed the 8gb ram back again. Now the computer doesnt boot in the os but bios is working normally. I tried also to install ubuntu , without any succes. What should i do ?? All the help will be appreciated. thanks

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It sounds like your laptop does not support 8GB of memory. – Ramhound Jun 25 '13 at 18:29
if i remove one RAM , and leave in only one slot with 4 gb , anyway the laptop doesn't but . But if i plug-in the previous both RAM cards with 1Gb and 2Gb , it works fine . – qrsq Jun 25 '13 at 18:35
Then it appears that it doesn't even support 4GB cards. Most likely the maximum, you can put in that computer is two 2GB cards. – Dan D. Jun 25 '13 at 18:42
doesn't support even if my laptop is booting on x86 system? windows is showing that only 2.99 of 8 is available. bios is showing 8192 MB. – qrsq Jun 25 '13 at 18:48
@qrsq - You have not even told us the model of the laptop. We are just guessing based on what you describe. Its even possible your laptop doesn't even have a 64-bit processor. Outside of that you don't describe exactly in detail what is preventing you from installing Windows when 8GB of memory is installed. – Ramhound Jun 25 '13 at 18:57

Their is a limit that the motherboard will use, as the BIOS will register it as 8GB but it boils down to these answers: 1. The motherboard only supports 3GB 2. Bad RAM (Usually follows with ether with a beep code or a "Lock Light" flash (Caps Lock, Scroll Lock, & Num Lock will blink, stay solid, or flash in a specific way to show that something is wrong as it will be like a code for a diagnostic code. 3. The clock-speed does not match the boards maximum or minimum speed specs. (hint: where the power is try placing in power-high speed configuration (what i call: i.e. highest speed in the slot closest to the power socket. (Only tested in Desktops, I have not done it in a laptop as the RAM is more expensive.) 4. If the hard-drive was was swapped (i.e. 5200rpm -> 3200rpm external format speed).I did that with a widows XP laptop, CPU 1.2GHz with 5200rpm -> 3200rpm result of a CPU speed of 833MHz. 5. The clock-speed of the CPU is slower than the RAM (Not Recommended as the CPU will not be compatible for boot, Ram speed shall not exceed CPU Speed as said for maximum and minimum RAM specs.) 6. The minimum requirements for Windows 7 for best result is 4GB witch will leave room for play (Inconclusive Answer as i was also looking for minimum but was given different answers from sources by Google and Bing as all to most were forums)

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