Hey guys,

Ok I've been having some PC problems for the past 4/5 months now

1. My PC started making a loud, grinding noise.

2. CPU began overheating, causing random unexpected crashes, so I re-applied thermal paste and REPLACED the heatsink (no resolve).

3. I then found out that for some REASON, the MB's 'Fan speed control' feature suddenly wasn't functioning correctly (fan speeds were very low) so I tried updating BIOS (no resolve).

4. I disabled the MB's FSC, keeping my fans going at full speed. This has resolved my cooling problems (although not idealic, since I still don't know the cause for my MB's FSC disfunction) but I'd still get random crashes and MB beep warnings.

5. I then turned to the SYSTEM, updating everything. Cleaning, virus scans (etc) and tried restoring the system files using sfc /scannow, but unfortunately, due to me having updated to SP3, I was unable to replace the 'broken' files the scan found with my CD (the files are probably just those that I'm aware of being modified anyway).

6. Backdated my system to SP2, then spent days updating SP2 with all Microsoft critical security updates to the point of SP3 release (no resolution).

My PC functions fine in safe mode, I don't get the grinding sound, MB warnings or crashes, which is suggesting to me that it may not be a hardware problem? (someone suggested that it could be the PSU, but wouldn't a PSU problem prevent the PC functioning at all?).

During 'normal' mode, the grinding noise is very loud and I get MB beep warnings and crashes. Sometimes I'll get MB beep warnings and no imminent crashes, and other times I'll get no MB warnings and crashes. The MB beep warnings are random: sometimes 1 single beep, sometimes 2 with about 2-4 seconds time between and on occasion, I'll get 3 beeps with 2-4 seconds between.

The crashes aren't instant power off types though, they're like system shut-downs (if I have a document open I'll get a message like 'Save changes?' sort of thing, but it won't wait for me to decide, it'll shut down regardless) and If I restart the computer immediately after one of these crashes, Windows will start but then instantly shut down with a message such as 'DWWIN.EXE could not initialise because the system is shutting' (or something, DWIN is the most common one, but I've seen multiple .exe file names as well).

Specs:

MB : Intel D975XBX
CPU : Intel Core2 Duo 6700 2.66
PSU : Cooler Master 550w (RS-550-ACLY)
RAM :
SP2

(I'll update specs in just a sec)

So yeah, idk what else to say really

*EDIT* apart from: safe mode is really dull Can you isolate the grinding noise to any spot it isn't comping from the motherboard it's probably one of the cooling fans are the hardrive maybe the cd rom take of the cover and listen and find were it's coming fromok I'll do that now.Ok there was no grinding noise and it worked fine for about 10 mins. Then I got 1 single beep and shortly afterwards (about 5 minutes later) the grinding noise returned slightly and the comp shutdown about 10 seconds later.

I think the noise is coming from the PSU but I can't be 100% certain since I don't know what else could make that noise. I only had a few seconds (as I said) to identify it but it's definitely coming from the back where the PSU is.

At the back I have PSU, heatsink (which is new), chasis fan (which I doubt would cause an instant shutdown like that?) and a graphics and sound card. The fan on the graphics card is tiny and makes a 'skimming' noise.

In safe mode, does the system not require as much power?

Could it be my graphics card? (in safe mode it isn't used?).Borrow a known good PSU of the same or GREATER wattage and swap it in there...
You'll know soon ENOUGH if that's the issue or not.
When's the last time you did housekeeping inside that case ? ?Quote

a loud, grinding noise.