Mass D/C in every mmo

Recently I've been trying to play some mmo games but somehow I d/c in all of them so far.

Three ms p.servers (one was asked to join with a friend, the other two were tests for the d/c). They were all developed pretty far, ie. Dedicated servers.
Dragonica
Valkyrie Sky

In dragonica, I d/c within the first minute of entering an instance.
Valkyrie Sky, again I d/c when I go into an instance.
MS just d/cs when I hit a monster. However before I moved, I already d/ced frequently on gMS (once every 2 hours or so), but not on p.servers (very rarely).

This only happened recently when I moved into a new apartment. My brother is playing on his computer with NO problems whatsoever (playing Aion). I also netplay a fighting game and I don't d/c or lag that much unless the guy is across the world.

Prior to moving, I had no problems with Dragonica (SEA version too) or any ms server.

I am running Vista. My bro is on Vista too. What can be possibility for my mass d/cing?

So what is the problem here? I am running vista.

P.S This is not a thread discussing p.server morals.