serach product with their specifications filter

I have a table that contain products with their specifications.i created a sample of data in http://sqlfiddle.com/#!2/15575/1 .I want create search form that users can search products by their specifications.for example user search laptop with RAM=2 and VGA=512 or VGA=1.
I wrote a query,but not working.please help me.
this example:
result: 1525,1535,k5,k6

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