The first thing I am going to suggest is Check for windows updates manually. ORb ( start button) whatever, all programs Windows updates. Do all updates reboot if needed and check again. that is to be sure any security leaks windows caught are fixed. ( pathced )
Then from there, look closer at installed programs, For example if you have Bit torrent installed, check program file foldesr for added on programs, this happens when people just install and do not do a Custom instalation. Other Tool bars or programs get installed. Third, check your browser tool bars. if you have alot of them they all communicate. I suspect it may be a communication program hogging power and bandwidth. OR a virus. but we arent there yet.
IF no updates. Check the programs installed as mentioned above. ( physically look in programs files and Programs ( both program directories in C: )
also unhide folder files checking Local folders and local low MS folders for installed hidden plugins programs.
hope this helps.