Windows 7: Slow Connection

Hi guys,
I have some problems with my internet connection. My Seven version is the 7100 and since yesterday I'm experiencing slow connection problems. I can surf the internet as fast as I surfed when I had Xp, but now I can't download fast programs with my browser (Opera 9.64) or, for example, I can't log in skype.



Moreover, I think that the problem could be caused by a windows update because at the first start up, everything was going well.

Could you hep me in some way?
Thanks and sorry for my english.
Bye

EDIT:
I have to modify what I said up. Now, after using the compatibility mode with skype, I can use it completely. Now it's working.
Remains the problem with Opera, maybe because it's not in compatibility mode, or maybe because doesn't officially support seven. I'll try now to set the compatibility mode, then I'll let you now how works (at the moment the problem is with the downloads and with some internet pages).
I tried with IE8 and I don't experience problems with it. So maybe, it's only an Opera issue.

EDIT2:
I set Opera to run in Compatibility Mode as Xp SP3, but anything doesn't seem to be changed very much. I'll try to download something to understand better the situation...

EDIT3:
Nothing changed. I download, if I'm lucky, at 10Kb/s but usually I downloaded at 150Kb/s when was going bad. With IE8 I stay on the 75Kb/s, but this is in any case slow for me.