My MacBook Pro just froze, any advice? So, my MacBook Pro froze three times today, two of which about two minutes after startup. I could hear fans making noise. When I say 'freeze' I mean that both input an UI don't work.

I tried Apple Hardware Test (not the extended test, the quick one). The first time it reported an error, then I detached all the peripherals (that is, an iPhone), retried it and it said "no trouble found". Tried it a few times again and it reported nothing, even with the iPhone attached.
The error code was 0xae81a618, but apparently it doesn't show up on Google, so I can't do much with it.

A while ago I had to use iDefrag because the computer was slow as hell. Apparently the hard disk was very fragmented; after using iDefrag it got fast again.

And by the way it just froze again, I'm now using an iPhone to write this. This time there was no fan noise, and I only had Chrome running. What do you suggest? Do you suspect it is an hard drive problem? Or a RAM problem?

Meanwhile I'm doing the extended hardware test, I'll post the result here as soon as it's done.

Update The extended hardware test 'froze' (input still working though) at about 25% so I just shut down the computer. Then turned it on after a while and it still hasn't frozen since then.

Update 2 Here's a copy and paste of the latest lines (which I think may be relevant) in system.log after a freeze (and subsequent hard-reboot). This time I had just put it to sleep.

 Jun 11 16:56:02 pt2ph8 SubmitDiagInfo[963]: Cleaning up expired diagnostic messages database at path: /var/log/DiagnosticMessages/2011.05.12.asl
Jun 11 16:56:02 pt2ph8 SubmitDiagInfo[963]: Cleaning up expired diagnostic messages database at path: /var/log/DiagnosticMessages/2011.05.11.asl
Jun 11 16:56:04 pt2ph8 system_profiler[964]: could not convert interface name
Jun 11 16:56:05 pt2ph8 SubmitDiagInfo[963]: CFReadStreamCopyError() returned: The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)
Jun 11 16:56:05 pt2ph8 SubmitDiagInfo[963]: Failed to submit crash report: /Library/Logs/DiagnosticReports/HWNetCfg_2011-06-09-234746_localhost.crash
Jun 11 16:56:05 pt2ph8 SubmitDiagInfo[963]: CFReadStreamCopyError() returned: The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)
Jun 11 16:56:05 pt2ph8 SubmitDiagInfo[963]: Failed to submit crash report: /Library/Logs/DiagnosticReports/HWNetCfg_2011-06-11-140841_localhost.crash
Jun 11 16:56:07 pt2ph8 SubmitDiagInfo[963]: CFReadStreamCopyError() returned: The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)
Jun 11 16:56:07 pt2ph8 SubmitDiagInfo[963]: SubmitProblemReport() failed with error (2)
Jun 11 16:56:07 pt2ph8 SubmitDiagInfo[963]: SubmitDiagInfo failed to submit diagnostic messages!
Jun 11 17:01:57 pt2ph8 loginwindow[46]: loginwindow SleepWakeCallback WILL sleep
Jun 11 17:04:43 localhost com.apple.launchd[1]: *** launchd[1] has started up. ***
Jun 11 17:04:51 localhost DirectoryService[11]: Improper shutdown detected


Update 3 Yesterday I was running Windows (installed through BootCamp) and it froze again. Then I rebooted with Mac OSX and watched a movie for about two hours, then after about half an hour it froze again. So I guess it must be an hardware problem, right? 

Update 4 it has been working without freezes for about three days now. Played games, watched movies from both Mac OSX and Windows. Should I still send it to Apple? And if so, now that I'm unable to reproduce the problem, what should I tell them?
some basic things - but you probably already done them:


Console.app (check log-files)
ActivityMonitor - check activity for HDD, memory, swap etc...


here are other helpers (command line) - but 1st you should check the above two...

Start with "all messages" or "system.log" and try search for repeated messages what can suggest something. But you will see much cryptic (but otherwise harmless messages) - it is hard to advise. Simply read thru - maybe you got some idea.

Here is an nice dashboard widget - iStat Pro - what show your fan speed, HDD activity etc.. Maybe can give an idea what is doing inside...