Yea...I'm on a role answering these unanswered help help questions...lol. A long...LONG time ago, when I 1st learned of the HBB bodyshape, and all similar shapes, I went on a downloading binge and snagged up every piece of CC available for them at the time. (Which was late 2007.) But when I added them to my game, a lot of the meshes were showing up looking the same as how you described, some HBB meshes and just about all of the BBB (Bear Bodybuilder) meshes. I came to realize that there was absolutely nothing wrong with the meshes, it was my PC that was the problem. I had an old, outdated P.O.S. graphics card that could barely handle the work load. So I went out and bought me a better running one (Which is still outdated by present card standards) and the meshes showed correctly ever since. So the one piece of advice I can give you from my own experience is to update you gfx card. You can find decent powered stuff at a fair price these days. Just be sure to know what kind of card your PC runs (PCI, PCI-Express, ISA, AGP etc. Look up Wikipedia to find out further details.)
Also, try going into graphic options in game and ramping up the detail. That's a sure fire way to find out if you need a better card. If no visible change occurs at the highest possible graphic output, it's because your card isn't up to code. Then it's pretty much a no brainer that you need to upgrade.
Good luck. Happy simming...and all that jazz.
