I don't know how detailed I'm supposed to be so be warned: this might be overkill. But anyway. I'm running Windows XP Professional. Installed programs: AVG Free Edition, COMODO Firewall Pro, Ad-Aware 2007. The computer has three user login accounts, but only mine has admin privileges. All accounts have Firefox as their default browser, and I've set the Clear Private Data option to do its stuff after every session.

1. Warning bell: Task Manager became inaccessible.
I didn't think much about my computer slowing down until I found out that I couldn't access the Task Manager anymore although I had admin privileges. Googled it and found that the exact error message I was getting ("The Task Manager has been disabled by your administrator.") was a sign of malware. There were several ways of getting around it (link here). I chose method 2, which required me to type a certain syntax through the Run command. Problem of Task Manager solved, until...

2. Mistake: "Healed" a worm?
I got a "Found threat" message from my AVG, stating the existence of a worm (Sorry, I totally forgot what the name was. Didn't have the presence of mind to do a screencap). Several options were given, among them "Heal" and "Move to vault." I clicked "Move to vault" first, but I was warned that this was an important system file (I think it was an .ini file, autorun.ini probably?) so I just healed it instead.

3. Ad-Aware started acting up.
I opened Ad-Aware 07 immediately, did a scan and found no more than the usual dataminers, removed them. I thought, naively, that the problem was solved. Then I tried to update my Ad-Aware. I connected to the Internet fine, was able to identify which updates I needed. Updates were looking good, progress bar filling up steadily, then I got another error message regarding the installment of said updates.

4. Ad-Aware acting up even on Safe Mode.
So I thought, maybe I could update it on Safe Mode with Networking. I restarted the computer, got into the said mode. I was finally able to install updates for Ad-Aware. Only now when I try to start the program, I get this message:

"Application Error:
Exception EAccessViolation in module Ad-Aware2007.exe at 001C852C.
Access violation at address 005C852C in module 'Ad-Aware2007.exe'. Read of address 00000414."

What should I do? >_<