The developers of highly regarded and effective ESET premium products have an on-demand scanner with an uncommon level of utility. ESET rolls their own engine and defs, so this is an interesting and useful addition to one's stand alone arsenal. The program installs to Program Files (x86) and runs both onlinecmdlinescanner.exe and onlinescannerapp.exe. The data store is worth 284 MB, 35 files in 7 folders. Connections that close upon exit are maintained to several ESET domains in Slovakia (and for me in the US hosted by PSI) for update downloads and during the scan. If the latter behavior is for a cloud service, there is no mention of such that I can find but might hint at why the exes and the app are named as "online." The screenie composite shows the quite granular settings in Step 1 and the incremental update in Step 2. Step 3 is progress and step 4 the results. Other than a link to the ESET Web site in the fourth screen hinting at the premium products, the app is without nags. It seems the download is location sensitive so you should goobinghooducketc for it from you part of the planet. Oh yeah, it's free.
The ESET Online Scanner is used for many years by several forums where you can get one-on-one help in case of infection, as one of the mandatory tools you have to use. The US link: http://www.eset.com/us/online-scanner/
Tried it before. Was fine except for the lack of easy quick scan and the ability to choose what to do with potential infections after the scan. You have to manually select where to scan (which is good for custom scans of downloads, but not efficient system scans IMO). And you have to choose whether to quarantine or just list detections before scanning.