Printer runs slow and system activity jumps.

In the past week or so, my printer has gotten very slow. This seems isolated to one account. Also, after using the computer for various tasks for a while, the "% System" in the Activity Monitor jumps from about 1-2 % to 12%, and stays there indefinitely. When that happens, everything slows way down. The only way to recover is to Restart.

I have run Repair Permissions -- no change.

All software is current.

I have 585 GB free space on disc.

I have 4 GB memory, and always plenty of it free -- even when running slow.