Unable to access SMB-share in Windows 7

Thanks for the suggestions, but I'm still stuck. I checked if I could SSH into the NAS unit using PuTTY, and I could access the directories without any problems. I'm using this for my mediacenter, which is really the biggest problem with this. I can still access my school files through the web-interface or through my Linux-computers, so it's really just XBMC not finding it that is the biggest problem. Just for kicks, I tried to enable UPnP, and XBMC found one of my folders, but not the other one. It also streamed painfully slow, while it used to be blazing fast through SMB.

I would have just booted Ubuntu on my desktop whenever I wanted to use XBMC, but I was a bit too quick when updating to 14.04 and I don't have sound through HDMI anymore, which makes Ubuntu useless for media. This is really driving me up the walls, and now I'm trying to solve the sound-issue in Ubuntu AND the SMB-issue in Windows 7, and both have a gazillion different solutions posted online, but none of them have worked for me so far.