I have read this thread but maybe missed this but you don't appear to have checked Task manager.
If you bring that up and go to the second tab, it has a column showing the %age use of CPU time for each running service\function. Looking down the list you can readily identify what is eating the cycles.
Thanks for the input cyclic, we used task manager, process hacker and process explorer which are more extensive versions of task manager, we evaluated every running process and application after which it was learnt that the system is infected with a Trojan: Win32.Sality and its variants. mmkarimi and layback bear resolved this issue, it took about 9 anti virus programs and a LOT of manual deletion to get the job done!
My Computer
- OS
- Windows 7 Home Premium 64 Bit - SP1
- CPU
- I7 3770 Ivy Bridge
- Motherboard
- AS ROCK OCZ Z77 Formula
- Memory
- 16GB DDR3
- Graphics Card(s)
- Nvidia GTX 670 4GB Version
- Sound Card
- Creative Sound Blaster Z
- Monitor(s) Displays
- KDS 23" Wide Screen Monitor
- Screen Resolution
- 1920 x 1200
- Hard Drives
- 2 x 10000 RPM Velociraptor 600 GB HDDs
1 x 5400 RPM SeaGate 1 TB HDD
1 x 5400 RPM SeaGate 160GB HDD
1 x External 5400 RPM SeaGate 750GB HDD
- PSU
- Corsair Professional Series HX 850 Watt ATX/EPS Modular 80
- Case
- ThermalTake Armor Series
- Cooling
- Arctic Silver 5 3.5G Polysynthetic Silver Thermal Grease CPU
- Keyboard
- Logiteh G510 Keyboard with LCD
- Mouse
- Logitech M310 Wireless Mouse
- Internet Speed
- 512 KBPS High Speed Brodband