You know an .srt file is a text file containing subtitles?
Do you have the video file associated with the subtitle file?
VLC Player will play the video file and use the .srt file to generate subtitles, but alone, the .srt file is useless.
If you want to use WMP though, try
DirectVobSub or
ffdshow
(
Once installed, make sure your .srt file has the exact same name as your media file.)