I have a Wolfdale1333-D667 motherboard with an Intel Core 2 Duo E8400. Power Supply Unit is a Cougar 700CM. I bought the motherboard two years ago with the system and had it put together by the vendor. The power supply unit was installed by me six months ago.
Recently, I moved and bought a new monitor at the same time. When I tried to install the monitor, there was an issue with nothing displaying, and during a restart, the hard drive died and the system wouldn't boot. I got a new hard drive and Windows 7 and started over. After that, my wireless card stopped working--it had always been weird, and folks online posted similar complaints about it, so I assumed it was just its time, so I got a new wireless card. Then, I came home the other night and my computer was unable to locate the hard drive (IDE1 slave not detected). After a few restarts, it did find the hard drive, and I was able to repair my installation of Windows. I shut off my computer and have not turned it on since (working from my macbook).
I would describe myself as somewhere between a novice and an intermediate, so I'm not too sure of my conclusions. Looking around at other sources suggests it might be either my power supply unit or my motherboard. The power supply unit is only six months old and seems to be well made, so I have a hunch it's my motherboard, which was a bargain with an Engrish manual made by ASRock.
Is replacing my motherboard a safe bet for making this thing stop killing hardware?
How hard is replacing a motherboard? I've done just about everything else (hard drive, graphics card, RAM, power supply).
Replacing your motherboard will stop these issues only if that is the issue. I still won't rule out your PSU, specially a lower end PSU like Cougar. I had a new Antec TP 550 die within a month, which Antec is one of the better brands. I would look to see if you can test your system with another PSU for a time and see if you continue to have issues. If you do, than the motherboard is a good bet.
As for replacing the motherboard, it isn't difficult if you know what you are doing. You will be bascially building the computer from stratch with a fresh install. There are many guides around that can help you out. You can check my "step-by-step" guide in my signature to get a general idea.
I decided to follow your advice and replace the cougar psu and replaced with it the old psu I purchased with the system two years ago. So far, so good. I'll give it a week and see if hardware continues to do as it should. I'll keep you posted. Thanks for your prompt response.