Processing advice

[delboy735]

Hi PH Collective. Looking for some advice about processing photographs. I have a basic DSLR ( Nikon D5100 ) and after years of fully auto, I've started to experiment with full manual mode etc, in particular, night shots of stars ( recently moved to West coast of Scotland so light polution pretty low ) and also waterfalls ( milky effect ). I always shoot jpeg, but am looking at changing to RAW, as I am told it makes for better processing. My question is this .....what processing program would suit my photography best ??
I'm not a fan of "changing" the taken image, at the moment all I ever do is level my horizons and crop ! So my brief would be a program that is simple to use ( I'm a bit thick ) excels at the basics, works on an oldish laptop. I've heard of people getting good results using "Lightroom", and also "Photoshop". Are there any more I should consider ??

Many thanks in advance :-)

[delboy735]

Wow, masses of info, thanks very much for your time. I've seen some of your work on here, and you all inspire me to learn more and improve my photography. I may even put some of my current piccies on for some hints and tips on where to improve