Hi ukblade and welcome to Daniweb forums :).
Download Ewido, install then from within the program check for updates BUT dont scan yet
ewido security suite: http://fileforum.betanews.com/detail/ewido_security_suite/1098736486/1
When installing, under "Additional Options" uncheck "Install background guard" and "Install scan via context menu". When you run ewido for the first time, you will get a warning "Database could not be found!". Click OK.
We will fix this in a moment.
From the main ewido screen, click on update in the left menu, then click the Start update button.
After the update finishes (the status bar at the bottom will display "Update successful"), Now close the program.
If you have problems updating see here http://www.ewido.net/en/download/updates/
Please download Nailfix from here:
http://users.pandora.be/bluepatchy/nailfix.zip
Unzip it to the desktop but please do NOT run it yet.
Next, please reboot your computer in Safe Mode by doing the following:
1) Restart your computer
2) After hearing your computer beep once during startup, but before the Windows icon appears, press F8.
3) Instead of Windows loading as normal, a menu should appear
4) Select the first option, to run Windows in Safe Mode.
For additional help in booting into Safe Mode, see the following site:
http://www.pchell.com/support/safemode.shtml
Once in Safe Mode, please double-click on Nailfix.bat. Your desktop and icons will disappear and reappear, and a window should open and close very quickly --- this is normal.
Then run Ewido, and run a full scan. Post the log from the scan here for me later when in a normal windows mode.
Then run HijackThis, click Scan, and check:
F2 - REG:system.ini: Shell=Explorer.exe C:\WINDOWS\Nail.exe
Close all open windows except for HijackThis and click Fix Checked.
Restart your computer in normal mode and post a new HijackThis log, as well as the log from the Ewido scan.