How can I stop my sound from fading in?

Try updating the sound chip/card driver. Check the online product page driver download page for Win 7 drivers available for the specific unit in question. Or go to the distributors download page, Realtek, etc., and download the 'latest' driver. List the system specs. No way of knowing what sound chip we are talking about.

I'll update everything when I get home, but I don't think that could be the problem as this computer is 2 months old.

Corsair 750 watt power supply
4 GB DDR3 Ram
i5-750 processor
5850 graphics card
1 TB f3 spinpoint harddrive
p55a ud3 gigabyte motherboard
Tuniq Tower 120 fan

The latest driver/utility downloads are available here for the board you listed.

http://www.gigabyte.com/products/product-page.aspx?pid=...
If using the MB's onboard sound chip, the latest driver for Win 7 is available here.

Click on High definition Audio codecs.

http://www.realtek.com.tw/DOWNLOADS/

Are you using Windows Media Player? When you switch to Now Playing, right-click and Select Enhancements, Crossfading and auto volume leveling. From here you can turn off Crossfading. Mine is set to 2.5 seconds using a slider.

Hope this is what you are looking for.

Did that and it didn't work, any other suggestions?

And MrToady, it happens when using WMP, Youtube, Quicktime, sound effects. Anything that plays seems like it has that crossfading thing going on.

Perhaps consider buying a dedicated sound card.

This hasn't always happened, so there has to be another way, something must've changed that I haven't seen. I do, however, want one. What suggestions do you have for an affordable yet powerful card?