Semi-Transparent World and Messed Up Sprites

Recently, every time I load some maps, the map becomes all screwed up with transparent flickering walls, ‘boxes’ around sprites (like lights, muzzleflashes, bullet impacts, and decals, and transparent/black weapons.

I took a few pictures of this in the map ‘De_DarkSanctuary’, although I have also experienced this in the map ‘fy_duo’. I would post them here, but I can’t find how to get the pic’s URL.

I tried loading ‘De_DarkSanctuary’ twice, and the problem was consistant. This doesn’t happen in other maps, though, like cs_office, gm_construct, cs_classified, among others. I truly HATE this problem, and I really want to know what’s happening. The real troubling part is that THIS HASN’T HAPPEND IN ANY MAPS UNTIL YESTERDAY! ‘De_DarkSanctuary’ worked fine when I first got it, but started being screwy recently. I have also deleted some recent addons that I got in the past week, but hasn’t worked.

My computer specs are:
Windows Vista Home Premium
483 GB of disk space remaining
8GB RAM
2.30 GHz processor
64 bit operating system

Feel free to PM me if you want.

You forgot to post your graphics card; it could be that causing the problem.

First of all, I can’t even find where it states my graphics card of the computer. Second of all, I’m pretty sure it isn’t the problem because I can run Modern Warfare 2 with good graphics and COULD run De_DarkSanctuary perfectly fine with fantastic framerates a few weeks ago but can’t now.

Start menu, then run, then dxdiag, then you’ll know what graphics card it is.

Alright, my graphics card is an ATI Radeon HD 3200 Graphics card.

Even if this isn’t good enough to run Gmod, it ran ALL of my maps fine until now.