Cisco WAN :: 2950 Switch Receive Configuration File From ISP?

At home I have a perfectly working test setup for more than 1 year now , but yesterday we had a power down for about 10 minutes in the whole area , after this power down nothing was working in my network any longer.
 
My Network is has follow :
 
ISP(Cable Modem) on FA23 from the CISCO 2950 SWITCH (24 Ports)
ROUTER (ON A STICK) on FA24 from the CISCO 2950 SWITCH
And the rest of the switch is FA1=VLAN 1; FA2=VLAN 2;FA10=VLAN 10
 
Our home network is connected to VLAN 10 with a IP Range of 192.168.10.x /24 After this power down , I was not able to look into the SWITCH via FA1 , the FIX IP in this switch was 192.168.1.251/24, the ONLY way to get access was via the consol port !!!What a suprice when I connected my consol to the PC , I can see ROUTER_F342 , my router config is called ROUTER1841 and my switch config name is /was called SW24.So it seems that after this Power Down , the router took or received a config from my provider ?!?
  
I have recovered the the file in the switch + the vlan.dat and now everithing works again.
 
How can I avoid that this switch receive again a wrong file , I have all the needed files on the products itself and I do not use a TFTP server.
 
I have atached some screen shot when my switch is starting up , and it seems that the switch receive a IP address from my ISP , I do not know why, in the config file I have given it a FIX IP 192.168.1.251/24 ?!?So it seems that my ISP erase the config file and when the switch is empty ,the  swich look for :

tftp://255.255.255.255/router-confg
tftp://255.255.255.255/ciscortr.cfg
Etc ....
Until it find something.
 
I have tried after a complete recovery to switch off the power again for 10 minutes (ISP MODEM + SWITCH + ROUTER) and I was not able to reproduce the fault.Can it be that due to this power failure in our area that some routers or switches send or broadcast this kind of things ?