do you have more than 1 hardisk? As Haarm would say, you need at least 3 drives. C: for system, Video drive, and a Scratch drive.
This is PR, not AE where you have RAM previews. PR does not have RAM previews.
If the timeline bar is red, it indicates that for fluid preview (not choppy) you need to render it first by pressing Enter. If you skip that step and just press the spacebar, no preview files will be created and the preview is likely to be choppy.
Putting you media cache on the C drive is not a good approach. It will require a lot of disk accesses from one and the same drive (Windows housekeeping, program, DLL's, pagefile, media cache, log files, etc.) and the limitation of all disks is that the head can only be in one place at a time, so it will be significantly slower and cause much more wear and tear than using multiple disks to spread the load. Hence the general suggestion to use at least three different physical 7200 SATA disks.
Oops you're right, I got my apps mixed up. I think it was the pause
and choppiness that messed me up.
Thanks for the drive suggestion,
I'll try it out. rC