I would like to think you should be capable even if you haven't built a PC in years.
It's all the same kind of stuff, just better performing nowadays. You still need to put the CPU in the CPU slot, plug in all your power supply cables, etc.
If you want help with the parts to pick out, either reply to this post or make a new thread with the following information:
What is your budget and currency? (Pound sign does not work normally, use GBP abbreviation)
Do you need a monitor?
Do you need a keyboard?
Do you need a mouse?
Do you need an operating system?
What will you use the PC for?