Please Help

I have xp home wth sp2. I am connected to internet and can search it. Over all internet seems to be running slow to. But when I try to logon to yahoo email it tells me Im not connected to the internet or my firewall is not connectng to HTTP, HTTPS, FTP. But I can turn off my xp firewall and still the same thing. I have ran adware, defrag, scan, virus scan. Still the same. I downloaded firefox and it will not find internet at all, but still connected. Any suggestions????

Dell laptop 1300 inspiron
512 mbs
1.60 ghz
xp home sp2
explorer 7

 

Thank you very much that fixed it.

 

bbolin06, Steve_East9 covered various points. When you say, 'that fixed it", what do you mean? Can you share with us some details on what, exactly, seemed to be the solution?