hi Nicky,,,, have you scanned your system for viruses and spyware.
If not then run a compleat virus scan with your anti virus software,,,, then download this spyware scanner, the free version ,,, update the defonitions and boot in safe mode and run a complete scan.
http://www.superantispyware.com/then download this cleaner and read the instructions in the links i also have posted and clean up your pc
http://www.ccleaner.com/http://www.internetrotsyourbrain.com/ccleanerbeginnersguide/http://www.timeatlas.com/tutorials/Ccleaner.htmsee if any of this helps,,,,,,, good luck