Hi,
Try scan you computer with Anti Virus,registry cleaner and spyware.
if you can do it in safe mode.
i use:
1. Nod32 Anti Virus
2. Ms-error Registry Cleaner
3.S&D spyware.
I scan and fix every month and have no problems errors or slow internet.

I had it too like many others.
i use the ms-errors registry cleaner run it once in a month i use the latest update and my i.e run great.
try it- ms-errors
good luck

One needs to have or develop some basic Desktop Skills in order to troubleshoot the browser speed issues. By doing so you can handle or troubleshoot the basic issues and keep your computer free from malicious content.