Windows 7 started to work slower and I used Autoruns, ProcExp and ProcMon to look at what was causing the issue. I found that it happened when DllHost.exe and WmiPrvSe.exe were running, but I'm not sure if these are causing the problem. But every time I stopped those tasks, the OS worked normally.
Now the same problem exists in Windows 8. Also, the HDD is being used 100 percent.
I've done some research in Win 8 and Sysinternals' Process Explorer told me that those processes are mainly run by svchost.exe:
D:\Windows\system32\svchost.exe -k DcomLaunch
This runs DllHost and WmiPrvSe with these commands:
D:\Windows\system32\DllHost.exe /Processid:{3EB3C877-1F16-487C-9050-104DBCD66683}
D:\Windows\system32\WmiPrvSe.exe
Note: Processid is not always the same
What can I do to fix it?