I'm running a 64bit version of Windows 7 on a computer that's a few years old. I recently installed malwarebytes, and found a few trojans and a good bit of adware. Aside from that, my computer is very clean. I quarantined the viruses, but just now my computer has been acting absurdly laggy, taking about 10 seconds to allow me to type anything into Firefox. I tried updating microsoft security essentials, which hasn't been able to update since November of 2013, and I keep getting the error message 0x80070002, I tried installing a new version of it completely, but it gives me the error message you see in the computer. Any help or assistance with this would be greatly appreciated.
I ran microsoftfixit, and it didn't give me results, if it was supposed to. It still won't let me update Microsoft Security Essentials however, and I'm getting an error message I was getting before, I forgot to mention it. Code 80070643, which it classifies as an unknown error.
When I tried uninstalling security essentials, it tells me it can't find some file like ess.msi. It gives me the error code 0x8007064