wierd switch activity

I have a small network of about 60 machines that connect via some unmanaged HP swiitches and a Cisco 1900 switch. This summer we moved the network around which cause lots of trouble with the CAT5 that had been in use sitting for 5 years. I have found out CAT doesn't like to be moved! The problem is that at least twice a day, the ports on the Cisco switch begin flashing wildly. they are green but flash much more than if there is normal activity. I have reset the switch a couple of times but it keeps coming back. And when this happens the network is inaccessable to any clients (win98 runing thru to a 2000 server)
Also when I try to connect a HP switch to the AX or BX port on the Cisco, it begins green then goes amber. Any idea what could be causing this and/or what to look for? Cables test fine 568B. It was working fine until the summer change....
many thanks
brent

The cable maybe to close and are cross feeding. Whether it be the other cat 5 , phone, data lines, or powerlines, it is hard to tell. Anyway what it sounds like to me.

Also, if you moved some of the cables and they are now close to fluorescent light ballasts or other interference sources, that could be a problem as well.

Yes I am thinking you are right jdc.
It is in an old school and it wasn't me who ran the cables so there a good chance they aren't run 100% correctly.
it is still amber but seems to be working.
i won't have time to check the route of the cable for a bit.