I have a friend who is having problems with entering a username on certain web-sites. This is only on his home PC.
On some sites he can enter his username and password but on others it gives him no white-space to enter them - or if it does it does not process them and let him log in.
He can get to all of the sites on his work PC.
He has run various types of anti-virus/anti-spyware, etc. He has cleaned out the cookies.