first download and run ccleaner and smart defrag 2 they will clean your registry and delete browsing history and other stuff. the defrag will defrag your hard drive and should make it faster. also make sure you only have one anti virus program as having two will render both useless. anti virus programs make themselves look like viruses so having two will make each other look like viruses and try to take each other out. atleast thats what i was told by my uncle who works for lenovo.
try that and see what it gets you