O.O 5 year old stock windows. Wow.
Ok. do you let this computer ANYWHERE near the internet ever? Does it ever have a live connection for more than a minute or two? If the answer is "yes", I'm guessing you're malwared up to your eyeballs. Not the stupid flash stuff either. the hardcore deep level stuff that basic computer hygiene normally protects against
Windows needs constant updates to keep ahead of the hackers, and virus protection programs assume those protections are in place. At this point I wouldn't be supprised if you wake up some night and find your computer busily impregnating your pets. Well, ok, I would, but you take my point. What I would not be surprised by is if you've actually got malware in your firmware that will resist a clean install. Yes, they can do that. Another possibility is that if you don't immediately update your windows, you machine is reinfected within minutes of the clean install.
This is the 21st century. You cannot behave like that anymore. Even Apple with it's tiny market share and unbelievably hide bound hear-no-evil, see-no-evil devs is targeted regularly enough that it gets regular security updates these days.
When faced with a system like yours, Before I'd even bother looking for hardware issues, I would;
1. Unplug from the internet.
2. Go find someone who hasn't treated his computer like a bus station bathroom and get them to download a bootable linux desktop iinstall to a cd, along with the firmware flash for the machine and peripherals.
3. reflash the firmware under linux.
4. Do a track independent bit level rewrite of the drive. A standard erasure won't cut it. There could be invisible partitions or something even more evil on there.
5 Connect to the net with the linux desktop and download ALL the current security updates for your windows as disk images along with some sort of antivirus software.
6. burn said images.
7. unplug again, and NOW do the clean windows install.
8. run the updates and install the antivirus software
9. Now connect to the internet.
if that didn't fix it you can start wondering about your hardware.
You will notice that nowhere in there was there any attempt to save any files. This was on purpose. If you're feeling lucky do a backup of the files to a disk before you start, and when you're done connect to it over the net as an untrusted connection. Run every piece of data through the virus checker BEFORE you allow it back behind your firewall.
Also, If you treat your new machine in the same fashion it will possibly be behaving just like the old one in very short order.
Edited by bombastinator - 11/19/13 at 2:14pm