Particle effects, some sounds, etc not working properly

[buggy]

I've tried searching for this, but as it turns out the servers are overloaded about 99% of the time so searching is impossible.

Many particle effects and some sounds do not work properly or do not show up at all. This includes warping sound and effects, many weapon effects, and more. Some sounds also only work about 50% of the time.

I have a feeling this has something to do with supporting libraries, like directx or somesuch, and I have to download a older version to get it to work properly. I think I might've even dealt with this in the past on other computers, but again I can't actually search so I can only ask for help here.

System info:

OS: Windows 7 Professional 64 bit, Service Pack 1, build 7601
CPU: Intel i7 670
GPU: Geforce GT 730
Memory: 4x4GB DDR4

[Genesis]

Have you tried running in compatibility mode? That fixed an issue for me where I couldn't see the login screen.