[Eliot Ness]

+1 on Mike's advice.  PB Blaster, Liquid Wrench, Kroil, etc. are all better penetrants than WD-40, but as Mike stated, in some cases, they need a lot of time and repeated applications to work.

As far as the screwdriver they are not all created equally; there are best, better, good, and downright crappy 

If you wind up stripping the head of the screw a high quality small drill bit will be your next option, and the same as screwdrivers, they are not all created equally.

I have found the Wiha precision screwdriver set to be a good investment:

https://www.amazon.com/Wiha-26197-Precis...ag=mh0b-20