Hardware Problem with my iMac

[Kibato]

I have serious problems with my iMac (21.5-inch, Mid 2010, 8GB Ram). I work mostly with the Adobe Creative Suite CS5, Windows XP @ VMWare Fusion, iWorks, etc, and now for the third time in a timespan of 4 months, the iMac freezes and makes an extremely loud (nonstop) noise.
This time I managed it to record a video.:

http://www.youtube.com/watch?v=EDJmZXDtZMw

I've already sent the iMac to a Service Provider some weeks ago and they changed the HDD, but it seems that this was not the problem..

Anyone ever heared such a loud noise coming from an iMac?

 

[Hellhammer]

Try SMC and PRAM resets.

 

[Georgio]

That is not good.

I remember years ago when we had the original G3's at work one of them suddenly gave out an ear-splitting screech followed by an equally loud impact sound, just like a traffic accident.

I contacted the company that were responsible for keeping the Macs in good order and he reckoned we had a terminal Mac which turned out to be the case.
It would seem that certain noises are programmed in to let you know a 'crash' is imminent.

 

[Kibato]

Try SMC and PRAM resets.

Already did several times.
Anyone knows a reliable memory testing program for intel based iMacs?

 

[Georgio]

You say you have 8GB of RAM installed.
Is the extra RAM a reputable brand i.e. Crucial/Kingston etc.?
If you look in profiler/memory, does everything check out in there regarding speeds etc.?
I would actually try removing the extra RAM and carry on working with the stock 4GB and see if that resolves it.

Already did several times.
Anyone knows a reliable memory testing program for intel based iMacs?

 

[interslicer]

thats a pretty horrifying sound. is it coming from a component or is it playing out of the speakers? if its a component sound, because of the repetitive nature im pretty sure it would have to come from something spinning. that pretty much boils down to HDDs, disk drives, and fans (including one on the gpu if applicable). if its coming out of the speakers it could be a software thing that poses no real danger to the computer. some times when things freeze they loop sound, but without more data on what was running, etc i couldnt tell you what it was.