What scan are you using and what settings concerning rootkits do you have? I may be that your rootkits settings are to high. And did you run a boot-time scan? If you run a boot-time scan I advise you to keep and use default settings. It could be false positives. Try using "quick" setting for root-kits not "full". You might consider getting MalwareBytes http://filehippo.com/download_malwarebytes_anti_malware/
And Super Anti-Spyware http://filehippo.com/download_superantispyware/
I think my system was infected at March 14. See my another post:
http://forum.avast.com/index.php?topic=73843.0Yes, I did run a full scan, the boot-time one as well. The detected file in Java cache was deleted. I updated my Java to the latest version, too. Another full scan at March 16. found nothing.
But however, yesterday I noticed a suspicious file in my Users folder named YCemSCi.exe, created at March 14. as well. And a few temp files. Fortunately this time Avast detected them (maybe, the new definition update!). I don't think it is a false positive.
By the way, all my settings are default (Normal).
What about SuperAntiSpyware Portable? Should I give it a try?