List your complete system specs, including your temps while playback time.
Run
Memtest to check your existing memory, and consider adding another 512 stick.
What antivirus/malware programs are running on your system?
Try StartupList :
Its a tool that lists all and every auto starting program on your system. You might be surprised what it finds, this is way better than Msconfig. Commonly used to troubleshoot malfunctioning systems, trojan/viral infections, new spyware/malware breed ect..
STARTUPLIST