Communication Problem

I have a machine that is connected to a hub. that hub is connected to the network gateway. I have redirected the connection so that the computer is connected directly to the gateway. but i think there is something wrong. [ when i ping from that pc to any other machine or even to the gateway i get one or two request time out ( out of the four ping packets). or i get Destination Unreachable message. When i ping from other PC to that PC i get request time out (all four packets) which means it isunreachable.
1. Do you think the cable is the cause of the problem..? (i am using Cat 5 patch cable)
2. Do think i shoud restart the router or something..?