i use intel's warranty swop web page, they do it for free if it is under warranty.They are really very quick in there swop outs.

Hi PC-Freak-

I have had a similar problem with freezups and reboots and I have the dp45sg board.

My system specs:

Operating system: Windows Vista Home Premium 64bit

Mother Board: Intel Desktop Board DP45SG

Processor: Intel Core2 Quad Q9550 @2.83GHz

Memory: Corsair XMS3 2048MB PC10600 DDR3  1.7v (running at 10600 and 1.65v)

Hard Drive: Segate 500 GB Serial ATA Hard drive
CD Drive: Sony 25X DVDRW SATA

Power Supply: Corsair VX550W 550W power supply

Video Card: nvidia geforce 8400 GS

I tried using the Intel Desktop Control Center.  I found the Test option on the right side of the control center and ran the Passmark Burnin Test.  The test checks components of your computer individually.  I found that the problem that caused my computer to freeze by running each test by it self and the test that caused the computer to freeze was the component that I took a harder look into.  In my case the computer locked up on the video tests.   Maybe this test can point you in the right direction...  Hope this helps...

I too am having this crazy issue & have been fighting with this computer since June 4th....

My System:

Case: Thermaltake Soprano RS
Motherboard: Intel DP45SG
CPU: Intel Core 2 Quad Q9550 SLB8V
Video Card: 1 PNY XLR8 NVIDIA GTS 250 1GB DDR3 PCI Express 2.0 x16
Hard Drives: 1 Western Digital Caviar Blue 500GB SATA II 3.0Gb/s
         1 Western Digital Mybook Essential 500GB SATA II External
CD/DVD Drive: Samsung CD/DVD-ROm Combo Read only (no recording)
Monitor: Samsung SyncMaster 220wm 22inch wide flat screen
Memory: Corsair 4GB 2x2GB Modules DDR3 PC3-10666 (1333MHz) - TW3X4G1333C9DHX
Sound: Integrated onboard sound
LAN: Integrated onboard Ethernet 1Gbit LAN (currently at 100mbs due to linksys router)
Power Supply: Thermaltake Black Widow 850watt TR2 RX-850
Operating System: Windows XP Pro 64-Bit
BIOS: Version 116
Anti-Virus: AVG 8.0 free edition
Keyboard: Logitech G11 Gaming USB Keyboard
Mouse: Logitech MX518 Optical USB Mouse

No overclocking has been done.

This ran fine for about 3 months with default settings in BIOS & I was using a PNY XLR8 Blue Hybrid 9800 GT Video card at the time.
CPU, Memory, hard drive etc. were all at default.

When I left the computer on 24 hours a day for these past 2 weeks, it began to lockup intermittently starting on June 4th, 2009.

I had BIOS ver 106 at the time & I've recently updated it to Version 116 to try and solve any issues but the symptoms got worse.

I dismissed it as a software problem, reformatted my computer & started from scratch by reinstalling Windows.

The computer locked up during the format at 29%... so I rebooted and tried to reinstall windows and kept locking up before setting up windows completely.

Replaced hard drive with another Western Digital SATA II 250GB to test and it ran fine for awhile then locked up.

Put original hard drive back, ran a quick format, reinstalled windows, drivers etc. (1.5 hours total install) played Fallout 3 & it locked up again after an hour of playing.

Had trouble booting.  It was turning on then locked up at POST.
I'm using default CPU settings the motherboard supplied but using recommended timings on the memory 9-9-9-24 at 1.6v

I've tried 3 different video cards,
PNY XLR8 Hybrid Series 2.0 1GB DDR3
ATI X1300 Radeon 512mb
PNY XLR8 GTS 250 1GB DDR3

Computer locked up on me after an hour or so on each card.

Next the network adapter started having connectivity issues & would still lockup after an hour.
I would intermittently have internet connection, then after rebooting several times I wouldn't.
I thought it was the linksys router but my other computer is running perfect with internet etc.

I turned off onboard LAN in BIOS, disconnected the network cable, played Fallout 3 for 2 hours & locked up again.

Fiddled with BIOS settings, loaded windows, played a song using windows media player on repeat for about 20 minutes, locked up again.

Turned onboard LAN back on, had connectivity issues, then after about 5 reboots my ethernet works just fine...
I can connect to my router and to the internet with no problems...

Sometimes if this computer is left alone for about 20 - 30 mins it will lockup.  I have no screensavers or power saving settings enabled.

Now my LAN is fine but I started having trouble with the sound... played an MP3 and got random skipping...
The IDT Software Audio Panel kept popping up saying I had a microphone in the front panel jack during the audio skips.
I have nothing plugged in there, only my speakers are plugged into the rear audio output jack.

I disconnected the front panel cable from my case to the P-Audio jack from the motherboard, reinstalled the audio drivers from Windows Update and now my sound works fine... & it locked up after 2 hours of looking for a solution.
I tried reconnecting the panel cable from the case to the motherboard but I get the same errors saying a Microphone is plugged even though none exist.

I thought it was possibly overheating but the cooling systems are running fine.
The temperature is always a few above & below the normal (green area) according to the Intel Desktop Control Center.

32deg. celcius for the inlet fan.
61deg. celcius for the CPU
35deg. celcius for the memory

The memory sticks have Heat spreaders & I'm using the Intel CPU Cooler that was supplied.
It stays optimally cool, the memory is warm and is not hot to the touch at all.
The same goes for power supply, CPU & fans.

I played GTAIV with no problems (about 2 hours), then I went onto the internet & played some web games on facebook & it locked up while I moved the mouse cursor over a game icon about 3 hours total.

I've tried the memory at 1.6v, timing at 9-9-9-24 (recommended settings) and it still locks up
I also tried setting the memory voltage to 1.7v.  Locked up after an hour.
Now I've set it to 1.5v & it locked up again while I was typing this note.

I've replaced practically everything except the memory, power supply & motherboard.
I've tried putting the memory in different slots but still the same lockup issue, even with just 1 stick it will lockup after some time.
I checked the windows event viewer and no applications are being shown as having issues.... it seems to be hardware related.

I cannot downgrade the BIOS either.

I figured it might be the power supply, but the ATI X1300 card barely uses any power & it does not require a PCIE 6 pin power plug.

Could it be the memory? I've tried all the settings for voltages. 1.5 - 1.7

Could it be the motherboard, since I can no longer use my audio panel connection from my case connected to the motherboard?

Update: June 11, 2009 11:23am EST:  I turned the computer on today and it locked up at the Video Bios flash screen before POST again.

It is now 11:55am &I've set the voltage at 1.3 and the temperature on the CPU actually dropped.

It is running at 47 degrees now which is way better than the 61.

I will continue to monitor what will happen after a few hours.

I'm almost afraid to re-connect my front panel audio jack back to the motherboard though, for fear of the sound getting messed up again but I will try that later.  I want to see if it will lock up once more after rebooting.

Thank you very much for the information.