It would help to know which file/s it was, and where it was located. I suggest you open a support ticket with Microsoft. They will confirm (or deny) whether it's a false positive. You can do so here:
Additionally, we have a CNET TechTracker Forum. Another member posted at the forum, stating MSE detected a couple of his files as Adware:Win32/opencandy.
I strongly urge you to open a ticket with the MSE Team, and have them analyze the file/s. There have been quite a few instances where MSE, detected Adware:Win32/opencandy in error. In the meantime, you can also upload the file to VirusTotal. It's a free online scanning service, which analyzes suspicious files. My guess would be, it's a false reading.
Let us know how you make out..
Detected by Microsoft Security Essentials Feb.20 during scheduled scan. False positive? MS descritionhere,