All backups will not run. Unique problem?

I have read through many other user problems, but nothing matches the issue I am having. I am using Acronis to back up several hard drives in my PC to 2 separate external drives. Call these externals H and J. Each one has similar settings : full back up with daily incremental.

Here is how I run it:
1. On Mondays, Drive H attached to computer. Run a full back up + 6 daily increments,
2. The following Monday I remove the drive and store it at a different location.
3. Plug in drive J, and do the same (run a full backup + daily increments) for a week
4. Remove drive J, store offsite
5. Reattach Drive H. Manually wipe all the backups on H
6. Start the process again (a full backup followed by daily increments).
7. repeat the cycle on a weekly basis

This system worked fine for at least 6 weeks, and then one day it simply stopped working. I cannot get Acronis to write a backup to ANY disc. I have deleted all the schemes I programmed, I have uninstalled and reinstalled the program, but nothing works.

When I try to reboot my computer, I get the "Operations are in progress, your system will shut down when these operations are complete". But they never complete, I have to force-shut down my machine.

I have build 6525.