What route into the pc do these things use.
You won't like what I'm going to say but here goes ....
In 98% of cases, it generally boils down to the users letting them in, e.g. :
- Inadequate or no anti-virus / anti-spyware / firewall running
- Operating your computer as "Administrator" ( not a "route in" as such, but it's very difficult for them to install themselves from other vectors if you are not running as Administrator)
- Clicking on things you shouldn't
- Not keeping your computer operating system and it's software up to date with the latest patches
Google is your friend, more than enough security advice already out there....e.g.
CERT - Home Network Security
Microsoft.com - Security At Home
BBC NEWS | Technology | Tips to help you stay safe online
The 20 Minute Guide to PC Security - IT Security
I would really seriously suggest re-formating and starting with a clean slate.... a trojan, virus AND a rootkit ??
..... please don't kid yourself that you can fix it.... your PC is in a real mess. Believe me, your time is much better spent re-formating and re-installing. I certainly wouldn't trust that machine anymore.
I will leave you to contemplate this quote.....
"When you are dealing with rootkits and some advanced spyware programs, the only solution is to rebuild from scratch. In some cases, there really is no way to recover without nuking the systems from orbit," Mike Danseglio, a program manager in Microsoft's security group, told a security conference in Florida. "Detection is difficult, and remediation is often impossible," he said.