No Response messages & computer shutting down, plus adapter driver missing (HP Pavilion m9400t)

Question

My desktop computer (HP Pavilion m9400t, Vista 64-bit, SP2) has slowed to a grind in recent months, and programs keep locking up, giving me a "No Response" message. This started with IE 9 tabs, then MS Outlook, and now it's every program. I often reboot to get it going again, but run into the same problem in a few minutes.
I leave the computer on overnight to run automatic back-ups, and now, the last two nights, it has shut down and won't start up by pushing the power button. The light stays on under the power cord. I followed the instructions on HP.com to get it going again, and it starts back up. How do I get the computer working smoothly again?
I just ran a registry cleanup and cut back on start-up processes. Virus definitions are up to date. I ran Malwarebytes and deleted one threat that was quarantined. I also ran hardware diagnostics, which detected a Toshiba RNDIS Adapter that is missing a driver, but I can't find the driver on the HP site. The details under Device Manager say the adapter is at Port_#0002. Hub_#0001. What is this adapter--a USB port?--and where can I find the driver?
Thanks for your help!

Answer 1

Hello lcafarel,
Let's do this.
1. Unhook everything from your computer but the bare minimum. This is just the keyboard and mouse
2. Unhook the internet modem if you are connected to a modem, if you are wireless, disable your wireless adapter.
3. Put the computer in a clean boot state, starting only the bare minimum services for the computer to run
a. Click start and then type msconfig.exe
b. Under General tab choose the option Selective Startup
c. Uncheck Load startup items
d. Navigate to the Services tab
e. Check Hide all Microsoft Services
f. Choose disable all
4. Reboot
5. Monitor for 24 hours.
I would assume in this amount of time you would be able to affectively reproduce the issue of the computer locking up and shutting down.
If it continues to lock up then we can start looking at the computer on an OS level.
If it doesn't continue we have to start ruling things out. 
First try plugging the internet back in, does the problem persist. Then start adding other peripherals back to the computer, e.g printers.
Continue to turn items on and add items to the computer until the lock ups and freezes occur. It's the best way to effectively isolate the cause.
As for the Adapter that is missing, it's something connected to your computer. Is it possible that you have a Toshiba modem that you are connected to for the internet?
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