My 2840 was acting up: slow to start up, slow to transfer files, and slow to profile.
First, I re-loaded the firmware, but it made no difference. Next, I ran a CHKDSK /F, and the problem went away. Something must have gotten fouled up on the hard drive.
Now, I run a CHKDSK /F as "preventive maintenance" every time I connect it to my computer. Can't hurt, might help.