My second floor lights does not come on when I turn on switch.. I even changed light bulbs and went down to basement and located fuse box and switched off and switched back on,but still not working... Could it be electrical wire? What can I do to fix the
Problem? Do I need to call professional service or is this something I could fix on my own?

It could be a few different things,trouble shooting electrical is systematic, best done by an electrician
The non working switch box needs to be checked for power
By checking with a voltage meter one of the terminals to ground then the other wire or terminal after turning on switch
Switches get slushy if there old it should have a distinctive click
If not you have to back up to the point were the switch is being fed from, this could be any outlet or other switch box
A lose connection on the hot or neutral in any box could keep the power from not getting to your switch or the lights not coming on
Good luck

Sorry caps lock button stuck so bear with me. Start by checking for power coming to the switch by placing a test led on the incoming black wire. The other led must touch something grounded or a white neutral wire. Can you do that?

Could be a bad switch or a wire loose in your junction box! Is it a single pole or 3way switch?