3com Switch Intermittently Losing Connection.

I have a 3 buildings and a network set up that consists of three UN-managed 3com switches that are interconnected together from one building to the other(each building has its own 3com switch). NOTE: The first building has in it a LinkSys WiFi(DHCP enabled) which is connected to from my ISP's router and then to the 3com switch in the same building. I found out that the DHCP coming from the LinkSys 192.168.x.x through the switches till it gets to the Ethernet Patch Panel at the second building have no interruption until it gets to the 3COM Baseline Switch 2016/16ports in the same office. I'll have to remove and re-insert the patch cable before there will be internet, even when the internet comes, it will be intermittent. But from the first building where the internet is coming from, I cant see any intermttentcy on the link. This happen almost everyday. NOTE: Each port on the switch were tested. The switch and the test PC were power cycled respectively, all to no avail. Yet the patched port on the patch panel keeps running with DHCP without running through the switch ports in the second building. Please help and provide a permanent solution to this problem. Thanks in anticipation.