Windows 7: Cant login websites without using proxy servers

Hi mates,
I have a weird problem nowadays. I cant login (not accessing) certain websites without using proxy servers with any browser. Some of sites say somethings about SSL, some of them take me to home page, and u know twitter, it says "somethings gone technically wrong" or sth like that. Even now, I connectted to proxy server to login here. So far now what i have done:
- The date & time are correct
- I cleaned cookies
- I resetted IE settings
- I rebooted my router
- I restarted my computer
Btw, I also have Ubuntu 12.04 and at there, everything works fine. So I think my problem is related with Windows 7.

I looked at net for a solution but there is not. I hope one of you can help me about this.
Thanks in advance...

Did you run any scans for malware?

yea i did. i already have an anti-virus and an anti-malware softwares on my computer. And I also scanned my comp.

Now I have a new problem. When I try to login my google adsense account it says your cookies are disabled. But in fact they are enabled. I dont know what is going on in my computer...