I had a problem with my electrical at home. I hope I could get some feedback here.

I experience some electrical spike at home. Whenever anyone switch on or off an electrical appliances, my speaker will "Dup". My friend told me it was irregular voltage. So far, 1 power supply (PC) and 2 DVD players have been toasted.

Should I call TNB or should I call an electrician?

in addition, after checking with my friend regarding electrical bill, I noted that my bill is far higher than my friend whose usage is slightly higher than mine. (No foul play) Is this somehow related?

old home but it was rewired by previous owner

???
I dont understand what u meant
the previous owner rewired his house for his own usage
i know because he left a few spots for future uses (which now is for my use)
I didnt pay him extra for the rewiring work also

anyway, I just want to know if this is 1)TNB, 2)Wiring, or 3)Area problem. and also how to solve it

I'll ask the electrician to take a check
before i install my home theater system