Very Weird Problem With Games.

Recently I got a new computer..And while playing World of Warcraft Ive been having issues such as, I cant attack, or chat, but i see everyone else moving around, i see others text, and others can attack me, sometimes when this happens i can use my pet and/or i can cast abilities, but not normal attacks, but thats only sometimes, mostly its just that i cant attack,chat. Well i had a similar issue in another game called Warrock, i coudlnt inflict damage, spawn, or chat. I know its not my internet connection because on old comp i didnt have this problem.

I thought upgrading my comp would help, i got 2gigs of ram and a 8800gt graphics card, with 500w psu.
Heres the link to the comp I currently have.http://emachines.com/support/product_support.html?cat=Desktops&subcat=T-Series&model=T3604.
BTW its vista, maybe thats the source of problem?

And I have did registery fix, defragged, and cleaned up with ccleaner.

Problem #1 eMachines.

Dont be a smartass.

I am sorry for some of our members immaturity, pretaz19. I would like to help.

Maybe it is a program running in the background? Is their any programs running?

If their are any firewalls running, or av, try disabling them.