I think Bigchuck has a point.
I have been using "Audacity" software which is available as a free download and performs really well, allowing multi-tracking, over-dubbing, editing, etc.
I also use a good quality Samson mic.
However, the sound card certainly is important. Any system is limited by its weakest link.
In my case, I think the dodgy link is me!

Remember that, depending on your own system, the input level of the microphone is adjusted by Windows itself.....go to "Control Panel", "Sounds and Audio Devices", "Audio". In that dialogue box you can select your input and output devices and also adjust volumes.
On my system, this operates before the recording software and really affects the quality of the recording.

I found this made a lot of difference....give it a try.
Also, check out Audacity....after all it's free!
Good luck