DSL speed problem

Hello. I currently am experiencing a speed issue with my 256k DSL connection. My main desktop PC does not seem to be receiving the full speed of the connection. The DSL connection hooks into a actiontec router and from there I utilize a wiresless connection to my second PC and Laptop. My main desktop that I have the problem with is connected using ethernet cable. My other 2 PC's have no speed problem it is only the one connected through the ethernet cable. I have attempted to solve this by changing the cable, hooking up through a USB connection, reformating the hard drive and reinstalling windows xp, deleted all cookies, installed spyware and virus scan as well as a program called content watch. I have called Qwest support & MSN support and both say that I am receiving a 256k signal to my gateway and say I may have a hardware issue. I went to PCtunup.com and everything checked out fine so I don't think that is the problem. My system spec's are 1.8 GHZ celeron, 512 meg ram, 64 meg gforce 4, 60 gig HD, windows xp. Any insight or suggestion would be appreciated.

Already did that as well. DSL reports indicate that my speed is what it should be to my router.