100 hits from 1 source to different ports/services over an extended period of time
is a hack attempt, not just a random port scan.
Mustn't be the case that it was really targeted at Atrocities PC - even DSL is some form of dial-up and gets changing IP adresses.
If a power surge is more likely to blame for the reboot I cannot say, as I don't know about the situation. (power network quality, the power supply of the PC etc) I know I had 1 reboot due to power surge in over 5 years - and that affected not only my 2 machines, but a whole lot of other things as well, therefore was quite 'noticable'. Surely "a little noise on the power lines" should not be sufficient to make a PC reboot, unless the power supply is really crappy or partly defective.
Concerning the router - there are more models out there then one could count, I guess. Everything that suits your taste and purse should be fine, as long as you stay away from those with known problems
See
this list for some (bad) examples ...