I need some advice ASAP. I've had my same PC for about two years. I have added a larger HD and maxed out the memory. For whatever reason I have developed a severe problem of dropping frames. I've tried all the fixes I've been tought but nothing seem's to be working. Is it possible the editing program has somehow developed a glitch? I use Vegas 5. Could that be possible? The film belongs to a friend and he wants them converted to DVD. They are your standard digital 8 tapes. I've had problems in the past but they were all solved with simple solutions and suggestions. Anyone have any idea's?
RAM is maxed
HD is 160GB
Defragged
Shut down all other active programs
Deleted all old video etc
Backed up all my music and deleted all songs
I have no clue.

Did you try another firewire cable?

Do you have SMART enabled for your hard drive? (Self diagnostic hard drive feature in most modern hard drives) Often, the default BIOS setup setting on motherboards is to have SMART disabled, so you won't see it reported if the hard drive is starting to develop problems and trying to report them. If SMART is disabled in setup, I'd enable it. You might run a thorough ScanDisk, especially if SMART was disabled (takes forever, so do it overnight).

I'd give WinDV a try. It's a freeware DV capture utility that buffers input (lots of payware doesn't do this). It might overcome the problem (in the meantime), even if the underlying problem is still there.

I have problems when I use the firewire port on my motherboard, when I change to the port on my Audigy card everything works fine, 2 hours with no dropped frames. This generally gets me if I have moved something and not used my system for a couple of months.