Hi, newbie here and I got a problem, duhhhh, could anyone be of some service?

I get and error message saying that my task manager has been disabled by the admin (which is me). I have found a program to re-enable it, but every time I restart the computer, task manager has been disabled again.

This all started when some how I got infected by a virus (don't know name) & adware. I have ran anti-spyware & virus software. It seems the virus has been successfully deleted, but I still have the adware & a Trojan coming back after each scan & deletion. The names of the 3 adware/trojan I have are:

Trojan Horse: vesbiz downloader
Adware: letsroll911.org hijacker
Adware: ist software

Procedures done:
1. Ran SpySweeper & Norton Virus scanner in safe & normal mode.
2. Cleaned Temp folder, Temp Internet, Cookies, and IE history.
3. When I ran the scanners I made sure the adware/trojan wasn't running in memory (by going to task manager).
4. Updated Windows

I don't know if this would be of any use, but my ZoneAlarm has alerted me that kernels64.exe is trying to access the internet and this has never tried to access the internet before.

Any help would be appreciated! Thanks

BTW, I’ve heard a lot of people saying use “hijack this”. What is this program and what does it do?