Jeremy, seeing as how it worked fine before, something has changed to affect performance. Have you installed any new hardware or software lately? Anything? Updated any drivers?
While there's always the possibility that you picked up some spyware off a website that is eating computing cycles, these things usually don't slow down overall system performance that much. A good test of this is to boot your PC, then go right to Wavelab without launching any internet software first. If Wavelab is still hiccupping, then it can't be spyware causing it.
I would venture to guess that you installed something new lately, and the driver(s) for it are slowing everything down. If you have installed anything new, visit the manufacturer's website and download the very latest drivers.
Either way, I strongly advise everybody who uses any version of Windows to regularly visit
http://www.windowsupdate.com. Hackers are finding new ways everyday of making our lives miserable, and unless you protect your computer and yourself, you're just asking for trouble.