Dell Inspiron 15 3000 Core i3 is running low and stuck

Hello,

My Dell Inspiron 15 3000 Core i3 is a laptop computer running low and stuck open the google chrome. In Normal time (without open application), memory usage above 70%. I Can't do internet browsing. Please help me to fix this problem without an upgrade my ram. (ram is 4Gb). Sorry for my English.