there are enough applications available for Windows. Soundforge, Wavelab, ...even lots of free ones.
At first I would always try to get a good remaster. Only if this is not available I would spent time on this...
Most good audio software is working like this: while you listen to the music you can change the sound by using certain plugins like a graphic or parametric EQ, compressors, expanders, ...
The result can then be saved to a new file. You should always save the original files as your remasters also correct potential problems of your current audio setup. If you buy new speakers your remasters are maybe sounding bad again...
At first I would always try to get a good remaster. Only if this is not available I would spent time on this...
Most good audio software is working like this: while you listen to the music you can change the sound by using certain plugins like a graphic or parametric EQ, compressors, expanders, ...
The result can then be saved to a new file. You should always save the original files as your remasters also correct potential problems of your current audio setup. If you buy new speakers your remasters are maybe sounding bad again...