update your anti virus and run a scan of the entire system
as aford recommends, download malware bytes, update it, run a scan of the entire system
empty the cookies folder, empty the temporary files folder
click my computer, click control panel, click add remove programs, look on the list.
is windows search on the list? delete it.
do a system restore if possible, restore to a time before the problem started:
click all programs
click system tools
click system restore
check the box that says restore my computer to an earlier time, click next
select a bold date on the calendar, a date before the problem started, click next
follow through with the restore directions
restart the computer after it finishes
if the system restore does not work, select an even earlier bold date on the calendar and repeat the procedure
try this with at least four earlier dates before giving up and trying something else
install an all in one security solution, the type that blocks un authorized incoming connections.