主题：【求助】关于Dell笔记本运行慢和发热的问题 -- 渡泸

if RAM usage is also high, especially when your laptop is not running any applications. that means a Trojan, or backdoor virus.

then log in kingsoft.com ( JinShan ), there is a free online checkup,if you pay 10RMB, you could get 1 month service, they also have a special checkup for Trojan.

Symtec firewall also provide some protection, but not as good as Kingsoft.