It sounds like you have been infected with malware called a Dialer. It's job is to do just that - dial a number that usually adds $50 charge to your phone bill each time it connects - or some such amount. Be watchful of your phone bill when it comes.
For help in removing this dialer you need to run a little program called HiJackThis. This program creates a log. Then you paste the log into the HiJackThis forum here at Bleeping Computer. An expert will help you get rid of the malware on your computer. It takes a little time, and it takes a little patience and you must be good at following instructions, as there will be some to follow. The following instructions will walk you through the process of creating a log:FIRST
Read the Preparation Guide found HERE
. It is very important
that you follow ALL of the instructions found within. (There are many important steps in this guide that may clean your computer.) NEXT
Post your system information along with a brief description of the problems you are having, and your HJT log in the HJT forum found HERE
NOTE: Please, after you post your HJT log DO NOT make another post in the HJT forum until it has been responded to by a member of the HJT Team. The first thing they look for, when looking for logs to reply to, is 0 replies. If you make another post there will be 1 reply. The team member glancing over the replies might think someone is already helping you out and will not respond. So, just make your post and let it sit there until a team member responds. The volunteers who work that forum are very busy, so please be patient and wait. It can sometimes take a few days for a response. If after 5 days you still have gotten no response, then post a link to your HJT log HERE.FINALLY
If, after finishing your work with the folks at the HJT forum you have issues with Windows related to the removal of the infection, then come to the other forums and let us help you get your computer back to normal.
You are in good hands! Good luck!