Songs not synced

I purchased an LP from iTunes. I went through the sync process as I have done in the past (I will admit I hadn't done this process in about six months but, just the same). Well my purchase showed up in iTunes but I could not get it to sync on my iPod. There is still 3+ gig of space left on my iPod so it's not a space issue. I'm using a PC running Windows 7 Professional and I have the most up to date ITunes and software on my iPod, as I've been told.
Help! Thank you in advance.

If you already have music on your iPod, you need to be careful how you sync the new album you purchased from iTunes. If you do a straight sync it will replace the music you already had on the iPod with just the new album. What you need to do is create a playlist of the new album music and then only sync the playlist. I no longer have a PC to see what iTunes looks like from Windows, but I'm sure the options and preferences are similar to what I have on my Mac.

One more thing.... it might be a good idea if you backup your iPod first just in case....