Question : Can't ping one pc on one of my subnets but i can ping another on that same subnet

I have 10 offices on 10 different subnets I am 10.23.26.XXX they are 10.23.27.XXX and so on.
I have one pc on one of those subnets i can not ping. It is up and working (most of the time) I can ping the pc right next to it on the same subnet. Now the interesting part is if i loginto the pc next to it i can ping that pc. Kind of odd.

Answer : Can't ping one pc on one of my subnets but i can ping another on that same subnet

Hi guys thanks for all your posting. I found the problem and it was my A/V Kaspersky. the pc somehow lost the network agent that talks to the main server at my main office. Because of that the A/V could not get my policy and it was locking them down and hindering them.