HI

I find my computer's memory is lost and it is now running slow. My complete data is lost I also lost my some important document. So, please help me guys and tell me how can I restore my all data. Did I need any software of technical supporter for this ?

You mean your RAM is decreased ?
If you have more than 1 memory stick ie. ram in your computer, then sometimes if a RAM stick fails, it reduces memory but still computer works because other stick is working. It can be due to two reason, either you need to adjust RAM sticks , may be they are loose.. or your one of the RAM stick is dead. You need to add more .. buy new one!