Players, mobs and NPC's teleporting

First of all, I'm sorry for my English.
I know it isn't top-notch, but I'll try to explain my problem as accuratly as possible.

I searched around the forums and the internet but I couldn't find anything like this(correct me if I'm wrong or if I didn't search good enough)

Anyways, I've played GW's for like one and a half year on a normal-range PC, without any problems, untill it broke down. I now use an old PC, which can handle GW's on lowest setting without any problems. I don't have any screen lags, and I don't have any internet-related lag either. (My ping is usually around 50-100.)

This morning, I connected to the game, and went playing some Fort Aspenwood. Suddenly, I noticed that the players and NPC's were teleporting all over the place, instead of properly moving around. Whenever I double-clicked on another player on NPC, I didn't move to that target, I just teleported to it and started attacking/following it 2 seconds later. I mapped to some towns/outposts, but every player/NPC/mob just teleported around. I shut down the game and PC and I went to work. When I went playing GW's again (like 2hours ago), I noticed that everything was teleporting AGAIN. One of my partymembers told me I had to turn up my graphics a bit. I did this, and I noticed that everybody stopped teleporting. We started the mission, and all of a sudden, everything starts teleporting. I've tried turning up my graphics, turning it down, changin my resolution, used 'Auto-Detect graphics' (It just put the game on the lowest graphics possible, and resolution on 1024x768. It just didn't work, people just kept teleporting.

I don't have any screen lag, and I don't have any internet related lag. My PC works fine, and I didn't install any hardware software lately.

I really have no idea how to fix it, so, if any of you does, how do I fix it?

Thanks for your time.

If I understand correctly what you're trying to say, and if this is what I think it is, then this is a known issue when you alt-tab through your programs. It fixes itself out after a minute or so.

No, the problem occurs right after I start the game. Even if I don't alt-tab.
It's the excact same as the problem that you describe(I know that if you alt-tab this happens aswell), except that even when I don't alt-tab I have this problem. I even tried alt-tabbing to fix it, didn't work. Players just keep teleporting, and it never stops.

I've been gaving the same problem for about 1 week now, never happened before, and now it just doesnt seem to go away.. Does anyone have any solution?

Repair your gw.dat file might work. I'm really not sure what could cause this if it's not lag..
So repair or reinstall GW.

Have been away for some time, and it all seems fixed.. Didn't reinstall anything, it's just.. fine again, the way it was. Still don't know what caused this, but I don't mind - it's finally fixed.