I have repeated freezes when trying to use Safari after installing HD
I installed a Seagate 750GB 7200 RPM hard drive in my wife's MacBook Pro using your guide (excellent, by the way). Everything was smooth for a while, Mac ran a bit faster, now had plenty of room for updates, (original HD was 80 GB, full). After a couple of weeks, we have been having issues with the spinning beach ball of death. At times the Mac won't start up, sometimes when starting Safari the system just hangs.
So far I have zeroed out the data on the new drive, verified the disc and repaired it, repaired permissions and restored the system from my Time Capsule backup, but still keep having the same issue.
Should I be thinking about trying to get warranty coverage on the HD? There were no problems before replacement, the original was just full, or is this a software problem?