I quit stuttering several years ago, but my AL7.2 system just started.  The base problem is that playing back ANY video or audio in either source or timeline windows results in random frequent stuttering of both audio and video during playback.  It's pretty much unusable to listen / watch what I'm editing.  However, the files it outputs are perfectly fine.  It doesn't matter if it's multilayered, freshly captured or still frame, or if the audio is recorded, layered, or SmartSound generated.  The quad-core system has plenty of horsepower ... even when it's trying to play, and is set to higher priority, only around 12% of CPU power is being used, and there are no other programs registering as using more than 0%.  Drive transfer datarates are nice and high as they've always been.

This system is one that I haven't edited on for several months, but I have used routinely for other apps and have kept updated with MS updates.  I'm wondering if maybe there have been some WinXP updates that are messing me up.  

 Any thots? 

Stuttering as you describe is caused by something interfering with the disk I/O (Liquid can't get the data from the disk fast enough). The first thing to do is to defragment your media drives (both media and render). Also, unplug anything from your system that you don't absolutely need. If everything works, start plugging things in one at a time till they don't work.

Since you've been using other applications, make sure that none of them are running in the background. And check the settings on your antivirus app. You might want to turn off any antivirus and firewall applications (and unplug from the network if that makes you visible).

Also, be sure to don't have any drives fallen in PIO mode.

Right click on My Computer and choose Manage / Go in Device Manager / IDE ATA/ATAPI controllers:

Then, double click on your Primary and Secondary IDE Channel and go in Advanced Settings.

Check if you have your Channels in Ultra DMA Mode 5 or 6 (or 2 for some DVD burners).

If you have one in PIO mode, maybe you can try to uninstall the Channel and reboot your computer 2 times.