I'd recommend the free version of AVG for anti-virus protection (anti-rootkit is combined these days) - 2013 version just got released a week ago or so. Doesn't hurt to also have Windows Defender for anti-spyware.
http://free.avg.com/us-en/free-antivirus-downloadMy PC has a 640 GB HDD with two partitions, the 2nd one being only about 20 GB. I installed another copy of the Windows OS from the CD that came with the machine (Vista in my case) on that partition after I did damage to the installation in the 1st partition. Booted from there and did the fixing that I had to do.
If you have this option, that's one way to do it (
if you can boot from USB, and have a memory stick reserved for emergency purposes, that's cool too, but gonna be slow). That is, if you have two or more partitions, or at least two hard drives, you can install Windows to the other partition/drive and it'll make a boot menu for you to pick which one to boot off of every time (
boot sector gets overwritten per Windows install, so that's good). So, after completing the installation, you'd boot to the new install, download/install an anti-virus program, then run it on the drive/partition that got infected. A full scan of the whole thing will be necessary.
CCleaner... I use that program, there is no anti-virus feature in it.
Anyhow, before going that far, try just installing AVG on your current partition/OS and seeing if it can remove it while the thing is loaded with your OS.
EDIT: Not sure how you got the virus or if it's that spyware crap giving you fake reports, but the reality is you always need to have an anti-virus program running with "Resident Shield" protection that's constantly scanning memory and that is integrated with your browsers. I used to think I'd never get a virus cause I thought that only happens to stupid people who click on "I love you" emails and what not. But in '07 I learned just being on a webpage with IE, an exploit can cause the download and execution of a binary all without your knowledge... I was redirected to a page, next thing I know, my hard drive starts flashing like crazy from use, and then the machine reboots so that the virus could be permanently loaded. Long story short, I almost lost everything trying to clean it up. AVG knew the virus in question, but tough shit not having had it installed...
If you're paranoid, the best way to operate, albeit cumbersome is to install Microsoft Virtual PC (if using Windows), create a virtual PC instance, install a version of Windows, a good anti-virus program and browse the Internet that way. If you ever did get a virus, it would be contained within this virtual PC instance and all you'd have to do is delete the disk file that corresponds to it and restore from a backup from when you first installed the OS and anti-virus program. Pretty easy, really, but you need a fast computer so you don't get irritated by these extra steps... Just an idea. A friend of mine just uses another computer strictly for browsing, but with virtual PC software, you don't have to go that far.
For the virtual PC idea, here's a folder in "My Virtual Machines" that the program creates and I have these files in it:
Windows 2000 Pro Hard Disk.zip
Windows 2000 Pro Hard Disk.vhd (Virtual Machine Hard Drive Image)
So, if you caught a virus, you'd delete that .vhd file and unzip the copy you zipped when you first set it up and you'd be completely back to the way it was...
I have two instances, Windows 98 SE and Windows 2000 so far that are very useful for testing. They've helped me catch bugs for some of the applications that I've created over the years like TurboRip, TocFixer and other stuff, etc. The Ys IV dub even... But, I'm too lazy to adopt this browse-only idea besides my Vista machine not being fast enough... I just have AVG 20XX running and hope for the best.