When I start up my computer (Dell Dimension 4500), I've been getting a warning screen message (black screen with white writing).

This happened for the first time yesterday and happened again today.

From what I read, it appears to be a problem with my Hard Disk: "Pri Master Hard Disk: S.M.A.R.T. Status BAD, Backup and Replace. Press SPACE bar to Continue"

After pressing the SPACE bar, the computer starts up and continues to work with no problem.

I would be grateful for advice.