Adware:Adware (or spyware) is a small program that is designed to show advertisements (in various form and degrees of intrusiveness) on your computer. It often reports personal information back to its owners. As a result your sense of privacy can be violated.
MicroBillSys is a nasty application that is associated with several pornographic websites, including www.Sexxxpassport.com, www.Mysexworld.com, and www.Membersmatter.net. Once installed on your PC, MicroBillSys will persistently prompt you to buy a membership to these sites. You will get a three day "trial" period, but when it ends, the program may also lock down all Internet access unless you pay the membership fee.
Technical details (How to remove MicroBillSys(pop up))