Another useful little program is '
HiJack This' .... This will show you all files or processes running in memory on your system. This is highly technical but I look for processes that I have never seen before; I check the DNS setting shown to be the same as used in the network setup; I remove/fix any BHO (Browser Helper Objects) that may be listed; I note all programs shown as started-up which I use & remove/fix any that I don't use. ... For anything I don't recognize, I will google to find out what it does and if I should remove it.