my friend had this problem, and disabling kaspersky solved it!
he had also a problem at playing online game, but after disabling kaspersky it worked.

@Alibaba:
Yes I use Kaspersky Defragment also worked, but after 2 days it gets back, looks like I'll remove my Kaspersky (I got it as a gift, so it shouldn't be a problem with deleting it. I was happy with my Microsoft Security Eessentials )

@Dean:
Actually, it gives me some false alarms also. I know it has a good popularity, but for me it just ain't right. I even have no idea why did I installed it.

hmm weird, i've never had any problems with it at all.
Least you got the problem solved