Google redirects and more...

Hi everyone, this is my first post so I hope I'm putting all this in the right place. I've been having some issues with my PC, Win XP SP3, having fallen victim to some malware. Here's the story:

A few days ago Antispyware Soft pops up. At the same time I notice the Google redirect problem. I downloaded and ran Anti-Malware and Spybot S&D, in normal and safe modes, which found a number of things, including the rogue antispyware, but it doesn't fix the redirect problem. I had been using Microsoft Security Essentials; while it was running normally, it couldn't connect to update virus definitions.

Out of desperation, I found ComboFix and ran it, in safe mode, from a USB drive. ComboFix indicated that it found a rootkit problem; I followed all instructions to the letter, and it indicated the problem was resolved. It looks like it worked: no more redirects, MSE can update normally, all looks right with the world. I've run several full scans, including MSE, Spybot S&D, Anti-Malware, all come up clean.

I have the log for ComboFix, though the posting instructions here say not to post it.

Here's my question: how do I know if my PC is truly "clean" enough for me to resume normal use, and not to be afraid that passwords or other information are at risk of being transmitted?

Thank you in advance.

Hello,We need a deeper look. Please go here....
Preparation Guide ,do steps 6 - 9.

Create a DDS log and post it in the new topic explained in step 9,which is here Virus, Trojan, Spyware, and Malware Removal Logs and not in this topic,thanks.
If Gmer won't run,skip it and move on.
Post your Combofix and GMER log if suceesful.
Let me know if that went well.