I've found the easiest thing to do is the following :
-buy a portable drive which has at least as much GB as your entire computer (you can get them for about $70).
-get a disk imaging software and create a disk image of the entire computer and save it to the portable drive (this you can get free, I use Active Disk Image and I got it from download.com).
-then if you can't rid the infection just hook up the portable drive to a usb, hit "image to disk" option in the disk imaging software you have installed and in less than 40 minutes, you're computer is restored back to normal.
Fyi, I've used it and it's saved me from having to reinstall windows, reformat, etc. By using the disk imaging software, it restores everything the way it was (using the disk image you created and store on the portable drive).
This is way better than reinstalling windows. Reinstalling windows means you have to also reinstall every program and file you had by hand, one at a time, but with the disk image software it reinstalls the entire computer in one shot, windows, all your programs, all your files, right down to your desktop background!
Btw, a disk image is a replica of the contents of the computer - everything. And using this kind of thing beats having to reinstall windows and then reinstall every blasted program and file you had one at a time.
I love this thing sooo much, I only regret I hadn't used it the whole time I owned a computer.
P.S. So far, what I've done is to be sure the drive has nothing on it before restoring it, I've used a disk erase/scub program to erase everything (that way I know the infection and any damage it did is gone- reinstalling windows does this too, right before actually putting windows back in). I don't know yet if this is even needed since I believe the disk imaging software erases everything off beforehand. Next time I have to use it, I'll not use the disk erase program 1st and just use the disk imaging and see if it has erased the entire computer before restoring it back to normal - but I think it does from what I've seen so far. If it doesn't erase 1st, then you'd have to use a program to erase the disk first. But this still beats all the reinstalling of programs one at a time. 
I'm quoting my own post above for a reason. I have to add some things :
1. Using a disk imaging program
does erase everything that was on the computer during the restoration process. I just read the userguide that came with my program. So I no longer need to erase beforehand - all I have to do if infected is restore the saved disk image I have and any infection will be erased automatically.
2. The program I use isn't free. I forgot I paid $39 for it. Though there
are free ones if one looks.
Now, I must advocate something new (at least, I think it's new). The best way to rid any infection, a 100% gaurenteed way to be sure it's gone on the first removal attempt, is to use a program like mine to restore the saved disk image - cause in 40 minutes flat all infections are erased - that's 100% of the time - plus any damage to the computer is erased as well and the entire computer is restored like it was. Because of this result this type of program produces, I see
zero reason to continue along the "tried and true path" everyone else is using, where you find an infection 1st with scanning for it, then remove it, then rescan a few times to be sure you got it all - which doesn't always get it and sometimes results in reformatting. So, I've decided to
stop dealing with any infections that way ever again - if I get infected, I'll simply use my program to restore the entire computer in 40 minutes - because this route
produces much better results as follows :
-100% of infections are removed, everytime, on the first attempt.
-any damage from the infection is removed and computer is restored the way it was
-saves tons of time scanning, removing, and rescanning to be sure it's all out
-saves time trying to get out stubborn infections that no anti virus/anti spyware program is able to remove
-saves time trying to get out bad infections that keep reproducing themselves.
It's seems to me that with
all these benefits I've listed above, I'd have to be crazy to keep using the old way which everyone else is using. So in that case, if anyone asks including you, I advocate dropping the old method of scanning and hoping to remove it with antivirus and antispyware programs - just use a disk imaging program and when the time comes you're infected, simply restore that saved disk image and the problem is gaurenteed to be solved within 40 minutes.
Can't beat disk imaging programs for saving the day. Thank gawd I have it is all I can say.
Btw, after reading the userguide that came with this disk imaging program, I found out that's
one of the reasons the program was invented so clearly my idea is not a unique one since they thought of it first. And I agree with the people who make these programs, they're the best route to go to save yourself many headaches.