Thanks in advance for any and all advice.
Here's what has happened and what is happening:
While I was on a business trip my wife's computer was sluggish and eventually she got a BSOD. She attempted a reboot but almost nothing happened. When I returned home I tried to boot the system. The system got hung on the ASROCK splash screen before the POST beep. I tried a few times and got the same result. I noticed that I couldn't access a BIOS setup or a boot order screen either. I also notice that the keyboard lights were not flashing and the mouse was not getting power. I figured this was a mobo problem. bad news/good news. The mobo is a couple years old and I cannot find another to purchase. on the other hand, I built my kids' PC with the same mobo. So the plan was to cannibalize the kids' rig, replace my wife's mobo, and get a new mobo for the kids' PC. I would then do a clean install for the kids. They have lots less stuff to reinstall, etc.
So today I sat down to pull my wife's PC apart and figured "what the heck" and tried to boot it up. For some reason I disconnected the printer USB and moved the keyboard USB input to that port. Lo and behold, the machine booted up... Sort of. I got past the splash screen and was able to boot into safe mode. That was a plus, but everything was moving very slowly. So I tried booting normally and got in. I thought this was a victory, but everything was incredibly slow. I brought up the task manager and saw that the CPU was running at only about 4 - 7% and the RAM was pushing only 2.15 of the installed 4gb's. But just closing that task manager window took more than 3 minutes.
I decided to run a malware scan, so I installed Malwarebytes (took a while) and ran the full scan. The system found 28 potential registry problems, but a quick look didn't show me anything scary. I quarantined those and rebooted.
On the reboot I got a disk-read error. A quick CTRL-ALT-DEL rebooted the PC, but now I was concerned for the hard disk. So I pulled off a couple of important documents with password lists and such and set it to run a CHKDSK. It is running that check as I type this.
So here is my question: Does this sound like mobo problem? A HDD problem? a RAM problem? What?? I am confused.
My money is on mobo first and HDD second. I don't think it's a RAM problem, and why would a HDD failure of some kind cause the internet to move at a crawl? Unless it's something to do with the HDD being accessed to pull up the browser.
Any thoughts or advice is appreciated.
As mentioned, I have a new mobo on the way, so I can switch that out and reinstall if necessary, but if it's a HDD thing I don't want to waste my time on that.
Windows 7 Home Premium
4GB G skill 10333 RAM
750GB WD HDD
Asrock N68C-GS FX mobo
AMD 2.8Ghz Phenom II X3
ZOTAC Nvidia GPU (I forget stats)