First step is to update to 4.2.1.
Next step is to tell everything there is to know about your hardware and OS and drivers.
Thanks for answering. Here's some data:
OS: Windows XP Home, Service Pack 3
Direct X 4.09.00.0904 (Direct X 9.0c)
CPU: AMD Athlon 64, 2200 Mhz
1024 MB main storage
graphics board: NVIDIA GeForce 6800 XT (256 MB)
sound cards: Hercules DigiFire 7.1 Audio Accelerator, nVidia MCP04 – Audio Codec Interface Hard drive partitions: C: 51207 MB (6524 MB free), D: 33659 MB (4972 MB free), E: 71680 MB (7311 MB free), F: 81925 MB (930 MB free)
I'm working on the Premiere update at the moment. I'll get back once I'm done. I know my computer is a bit slow for video editing, but thing is, all worked well until a while ago, no major changes in the meantime. I'll report after the update.
Don't bother. Your disk, next to the slow CPU, is the main culprit. Remove all partitions, reformat the disk and install everything from scratch and add at least two physical SATA disks with 7200 RPM to your system. Not exactly what you wanted to hear, but with partitions and the fill rate, this is about your only solution.
Along with updating CS4, please go to both your video card's and audio card's mfgr's Web site and get the very latest drivers. There were recently several updates to XP (and I am sure to Vista and Win7 too), and these can render the audio and/or video driver in a heartbeat. Editing an AV file much more intense an operation, than is simple playback. NLE (Non Linear Editor) programs work much more closely with both the audio and video drivers, than almost any other type of programs.
Thanks for helping out. I know my sytem's too slow but it had been working like this for a long while now, and last night I found the real culprit here. It was one single audio clip which had been deactivated. I don't know why this disabled playback completely, but it did. So, if anyone here might be facing the same troubles, check all your clips...My project is back on track now, yay :-)
Good news, and thanks for reporting.