I have a Dell Optiplex 760 with Windows 7 Professional. Whenever I click any function having anything to do with Backup and Restore it starts lagging and opening the recycle bin takes forever. When I reinstall Windows, it seems fixed. I'm trying reinstall Windows 7, but the setup keeps hanging at 'setup is starting...'
If your Dell came with Windows 7 installed, use the restore feature to get you back to square 1.
You didn't say if you are using the Win-7 BackUp and Restore feature to a separate HDD rather than your primary system disk.
The initial BackUp does take time, as it creates a full image, then add incremental files as they change over time to that image, which is reasonably fast.
While it is creating that image, you shouldn't be doing other computer 'things' as it is faster and safer to let the application image unlocked files rather than shadow copy ones you are working with.