PLEASE help, major port and connection problem!

Okay, I am NOT a computer wizard, so I have no idea how to fix this.

I was online reading about telnet, and I downloaded PuTTy, a telnet client. I tried it out a couple of times not really understanding anything I was doing, but one time I got a message saying something like “this machine might not be what it really is” or some nonsense I couldn’t understand.

But after that, I’ve had a problem with ports on this computer. I cannot load Gmail, along with a few other sites like it, and when I try to log on to AIM it says “trying port 6000, trying port 6500, trying port …”

Please help me figure this out, I am so clueless. Thank you.