While trying to fix a PC problem, I thought I went to MSN's website to re-download a program. During the download, I received two Norton NIS2013 alerts for "Adware.Crossid Popup.css" and "Adware.crossid VID-Saver.dll". NIS reportedly blocked the threats and put them in quarantine. I drilled down through the HKU Registry, to the locations given, and didn't see any listings. Full scans in safe mode and regular modes showed no problems. I also ran a scan with the Free SUPERAntiSpyware and it didn't find any probems either. Can I assume I'm safe and I can continue repairing the PC?