Hard drive or logic board problem?

My iMac (mid 2010 27" 2.93 GHz, 12 GB RAM) is on the hard drive recall list; I was going to wait until the floods abated a little, but a couple of very strange things happened yesterday:

1. Woke iMac; cursor/mouse (USB wired) would not respond. Frozen. Had to plug it into another USB port - then it worked.

2. Wanting to burn a test movie to a DVD to check for quality issues, I went into Sys Preferences and set to never sleep, etc (which is what I always do). Burned DVD.

3. Wanting to open Sys Prefs again to change back my settings - well...... bounced in dock, and the name showed up in the menu bar, but it would not open. No window at all. Tried to do a restart - no go. Every time I hit Restart, the Sys Prefs name would show up in the menu bar and there was no response. Trashed the ,plist. No difference. At this point, cannot restart or shutdown via menu or any other way. Even doing a hard shutdown needed three tries.

4. Tried to power up - no go.

5. Plugged in one of my bootable clones. Tried every key command possible - no response. Couldn't Safe boot either.

6. Finally unplugged the power cord for 15 seconds...... after that, it booted up and showed all my external partitions.

7. At this point, the hard drive was extremely noisy, grumbling, grinding..... so I immediately updated my bootable clone. Tested it and it works. Will do a second one later once I pick up a longer FW cable this afternoon.

So, should I call Apple right now - or am I safe waiting a while? The hard drive noise has abated somewhat this morning and so far no problems....