I built my PC about a year ago. It has a Pentium D 805 overclocked to 3.3ghz, 2gb or DDRII 667mhz ram, and a ATI X800 XT AGP card. It has been running awesome. The dual core flew through everything. I used to be able to do so much at one time. I could encode a DvD, have a Game playing, browsing the web, have ventrilo going, all at the same time. Now all the sudden if I even try to surf the web when encoding a DvD it is sluggish. What could that be a symptom of? Could the CPU be going bad? My hard drive is defragged, I keep my disks cleaned up. Always on top of the spyware removal and antivirus. Thanks for the help.
Use the Task Manager to see if you've got other stuff running that shouldn't be when you notice the sluggishness. Monitor your CPU, GPU, etc temps -- perhaps the CPU is overheating and throttling back.
I have a 450w PSU, and I use Adaware and Spybot to remove my spyware. My CPU temps are sitting at 45c and GPU is at 44c. Processor usage when encoding and running the game sits right around 70% and I have 900mb of physical memory free. Haven't made any real changes to the PC. Not sure what the deal is.