File comparison with winmerge is really easy. You do not even need two files. You can fire up Winmerge Program Files > WinMerge > Winmerge.exe
The windows popups up with two editors one on left, one on right. Past some text in the left. Past the same text in the right pan. Modify it a little bit. Hit the referesh button and you just compared two files. It is that that easy.
Merging files using WinMerge
WindMerge is a powerfull tool for merging too files. In that case for example you have 10 lines in each code and there are 4 differences. Right click on each different and select move to the other side. Bingo you just merge the two files using a very easy interface.