I would also check the information on the NIC card your using. If that NIC (Network Interface Card) is only a 10/100 card, you won't get the best speeds out of it.

I would also recommend doing a driver update. Check on the manufature site of the Laptop you're using for any newer versions of the NIC driver. Updating that may resolve any issues you're having.

Also check the other wired ports on the router you're using. You mentioned previously that other users could connect wired to the router with high speeds, but were they using a different port on the router? Try the others. There may be some configs on there that are causing mismatches in duplex speed, ect.