USB-Blaster on Windows 7

OK, thanks vjAlter, that was the information needed actually. After a bit of searching I could verify that x64 does not allow unsigned drivers to be loaded (you can install them, but they will not be loaded). What one can do is the following workaround (applies to Vista x64 also):

Hit F8 while Windows is booting and disable the signed driver option under options. Note however, this has to be done each and every time the system boots.

Several fixes have been posted ranging from disabling signed driver checks on x64 alltogether, but it doesn't work on Windows 7 the way I googled it, and on Vista x64 it used to get broken by updates. The other option is to sign the drivers yourself, but to be honest, too much of a hassle, I start my PC at work only one time a day and pressing F8 then seems OK to me.