Last updated Illustrator CC 2014 works very slowly

Question

Hello everyone!
Today I reintall Windows 8.1 (64bit) on my PC with all possible updates. After this I installed Illustrator CC 2014. It began to work ve-e-e-ery slowly, to hang up. Often not responce to any command. Task manager shows that proccesor works for 13-15% and uses just one core (is it normal?).
Illustrator CC, which I use before reinstall Windows 8.1, worked well.
Configuration PC:
AMD FX-8320 (3.5@4 GHz, 8 cores)
32 GB RAM DDR3 1333
SSD OCZ Agility 4, 240 GB
Videocard AMD R9 270X 2GB
MB Gigabyte GA-880GM-USB3 (BIOS FFe 07/10/2012)
Tablet Wacom Bamboo Fun Medium (CTE-650) with mostly new drivers
Please, help And forgive me for my English.

Answer 1

When you uninstall Illustrator, the preference files might have been retained, and also any third-party plug-ins that are installed will likely remain on your system, either of those could possibly be the cause of the problem you are experiencing.
Preferences might have corrupted somehow. You can reset these by doing the following:
Launch Illustrator and then press Alt+Control+Shift (Win) or Option+Command+Shift (Mac) as you start Illustrator.
If you have installed any third-party plug-ins, I'd start by removing those first of all. Something as simple as an outdated font-activation add-in could cause start-up crashes. IOW: check first to see if your plug-ins are all compatible with the version of Illustrator you are using.
When Illustrator isn't launched. Go to the Applications/ProgramFiles folder on your computer, and locate the Illustrator program folder, inside it is a Plug-ins folder. You can check if third-party plug-ins are the cause of the crash by temporarily dragging them out of that folder, and relaunching Illustrator after that.
Hopefully Illustrator will launch past the Welcome Screen after doing that.
Let us know how you go. If you are still experiencing problems, see if you can provide us with some extra information such as whether you are on Windows or Macintosh, what system version you are running, etc. Mylenium has included a useful link for this as well.
Cari