Well a router would depend, I say you could fry it with lightning, and maybee the PC's will live.
I am suprised the cable modem just didnt die though...
Personally I would rather have dammage to my computer than my router.
Also, I betya it's just a power supply problem. However dell power supply's are propertiary and cost a fortune. If it's a decent computer, I would start with a new power supply \ case \ mobo combo instead of buying a dell power supply.