Need advice about Win XP going kaput. Could I switch to Linus instead? And keep NIS?

Hello!

 

I am trying to figure out what to do about Win XP losing support.

 

I have a question up on the Norton for Mac board about possibly getting a used Mac.

 

But I wonder, could a non-computer-person like me switch my very old PC system to Linux, instead of buying new hardware?

 

Or would that be too complicated? 

 

Is there anywhere *trustworthy* on the Internet (besides here), where people explain ...  slowly, in excruciating detail ...  how to do computer stuff to people like me? 

 

And if I were somehow able to do this, could I keep using NIS?  I like it and don't want to switch, so that would be a factor too.