PS3 Blues

Here we go again, exact same thing I went through in December. PS3 froze while playing GTA IV, disc drive stopped reading all disc formats. Turned PS3 off for few hours and tried again, it's alive.......for 5 minutes, system froze again. Now it won't even read the disc long enough to get past the loading stage. Everything else works fine, just the Blue Ray disc drive isn't working.

Called up Sony today and told them this is actually the replacement unit I received in February (after the disc drive on my 1st unit crapped out soon after warranty period expired), they have agreed to perform a "one-time-only" courtesy replacement since my original warranty has long passed. Would this be the same "one-time-only" replacement they sent me last time? Hopefully 3 times is the charm, can't take any more of this hardware crashes, which always seems to occur when I'm playing the latest awesome game that I've just bought (last time was Call of Duty 4, awesome!!)