You should not assume the problem is solved. The computer thought it needed this infected file because the infected file "told it" it was needed. It probably was listed as an auto start, possibly a starting service, very possibly have disabled all of your security programs, though they can look to you like they are working. They may even SAY they are working. System Restore isn't going to fix damaged programs. It might return "some" of the system files back but if your security programs were damaged, it is very possible they are still damaged. You said every program you opened wanted this file...what does that tell you?
You said this is a business computer, though not what operating system you have but you are taking a BIG chance not completing the clean up steps listed. MS issued a security patch several months ago which could possibly have prevented this. But most people who installed the patch were home users, businesses didn't bother, as of mid January, according to the article
HERE, it is possible that 1 in every 16 business computers have been infected by this.
I just worked for over ten days on a computer that was highly infected, and ONE of the infections was the Conficker Trojan. Every single security program on the computer was totally trashed and to begin with every single new one I tried was infected immediately. The owner HAD used System Restore to try to correct the fact that her security programs were no longer working and many of her other programs were requesting some strange .dll file in order to run. With her System Restore she did get the programs to stop requesting this file, but her the security programs were damaged.
It is your choice, but if it were my computer I would run the steps.