Hya Jan.
No real problems in youre logs , but you can fix this one with
hjt:
O4 - HKLM\..\Run: [UpdReg] C:\WINDOWS\UpdReg.EXE
And i would uninstall Logitech\Desktop Messenger in add/remove programs.
Also i would disable the Windows messenger service:
Please download
Shoot The Messenger
Download and run the small (22 kbyte) "ShootTheMessenger.exe" utility. It will display the current status of your system's Messenger Service. The button near the bottom of its window will allow you to set the service to whichever state — running or disabled — that you desire.
If, for any reason, you should ever choose to re-enable the Windows Messenger Service, simply re-run ShootTheMessenger to do so.
And it seems you have no firewall installed , have a look in our download section for free firewalls.
And last , can you do a search for this file ,
ahc.exe on youre pc and upload it to this site:
http://www.virustotal.com/flash/index_en.html
and report back the result of the scan , and the location/filepath of it?
It could be a legit Adobe file , but also a trojan with the same name.