Internet Problem

Hello,

recently i have install the win xp sp-2 successfully now system is working very fast except the internet. I have also checked the internet connection to the service provider. If i use that internet connection on the other system then its working very fast. so it is clear no problem with internet service provider.

Errors occurs while i use internet on my system
some time it gives SSL certificate related error
sometime content related error

even i open the google.com url its take too much some times its open then it visible only half page.

Kindly give me a solution.
Lalit Kumar