why my recorded sound file fluctuates after i record it. need your help on this guys.. thanks

What recording software are you using?
Try finding one called Audacity, very good at recording and it is shareware, so it costs you nothing.

thanks. i'll try it. by the way i'm using adobe audition software. but when i use sound recorder it still fluctuates

What microphone do you use at the moment?
This would look to be the problem, otherwise it is the recording hardware that could be at fault.
Also what do you connect your mic into? is it a sound card or motherboard audio?

maybe thats the prob.. i'm still using the motherboard audio.. i'll save some cash so i can buy a new sound card for my motherboard.. my cpu is not yet upgraded.. thanks

Do you connect your microphone through the pink jack or is it a USB Mic?

have you tried this:
Control Panel -> Sounds and Audio Devices -> Hardware Tab (Pick the one that relates to audio, I use Realtek so that's what mine says).
Click on properties for the one you selected, click onto the Drivers tab, and choose 'update driver' , then follow the on-screen instructions.