THIS MAY BE PRETTY LONG, BUT FOLLOW THIS STEPS AND IT WOULD HELP YOU
the best way to fix that is to turon on ur windows update.
go to control panel> security> then click windows update
once update is turned on, updates will be automatically downloaded.
the nest issue is about the trojan.
you may be already infected, so get an antivirus. you may download those for free. go to www.download.com, search for avast for free, then download it. once you have downloaded the installer, install it then scan. scanning will remove the viruses.
step three is removing avast. uninstall avast, then get a firewall. if you dont have a good firewall, the built in firewall in ur pc would do.
again, go to control panel>security>then click turn firewall on.
step 4: get a new browser like mozilla firefox.
back to www.download.com, search for mozilla firefox, download it, then install. open firefox instead of internet explorer.
note: you wont get updates for ur pc if you unplugged ur connection
hope this helps