securiy certificate problem over proxy server

I'm currently using proxy server to online. There is some security certificate problem which disallowed me to connect to several site like hotmail.com and register.hp.com which require certificate verification. This problem seem like just for my computer because other housemate connecting to internet through proxy server doesn't have such a problem. Why is it so? Any resolution for the problem? Pls don't ask me to format my computer and reinstall everything. Really hope that someone can tell me what actually happened.
Thank you.

 

Do you get an error message?
On my old computer the bios info had to be reset after rebooting. If i didn't correct the Year on the OS i would get a certificate error when going to Hotmail.com. Make sure the date is correct.

Rookie
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Yes, I do get an error message stating that the certificate is invalid or not yet valid. It is then lead to a 404 error page of my ISP. This problem only occur when I connect through proxy server. It does not appear when I connect to internet directly. I'd checked that my system date is correct.
Thanks for reply.

 

What proxy server?

 

I'm currently using Proxy+. This problem doesn't occur on any other computer connected to the host. Just to my computer.