I just looked the file name up on dr web. It says it's a mass mailing worm. I suggest if you have a Antivirus program installed I would run a full scan now. If you don't have one, Avast Home is good. You can run a boot time scan and the program itself scans emails as well as everything else.
I will run dr web on my computer to see if I get it, it may be a false positive.
The themeui.dll is a system file pertaining to Themes.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Airbot 2.0
OS
Windows 7 Ultimate x64 SP1
CPU
Core i7 920 (D0) @ 4Ghz, *26c idle *65c full load on air
Motherboard
Asus P6X58D Premium - Sata 6Gb/s - USB 3.0
Memory
12GB DDR3 Corsair Dominator -CMD12GX3M6A1600C8 at 1600MHz
Graphics Card(s)
Zotac Geforce GTX 770
Sound Card
ASUS Xonar D2X
Monitor(s) Displays
1 LG 24" Flatron W2453V-PF 1 Samsung 24" P2450H both 2ms RT
Thanks for your prompt reply. I did the upgrade from previous build and seems I cought it somewhere on the net. Just restored the original one with "sfc /scannow" command and doing the full hard drive virus scanning...