Malware Search.sidecubes has affected by mozilla firefox
Using google, I uninstalled all programs which could be related to searchcubes, further I deleted all add-on's and also checked regedit, about:config, checked folders in ../users/appdata/local/mozilla etc etc. I managed to get rid of search.sidecubes getting set as homepage.
But now even after selecting google as default search option (including about:config page), whenever I search anything in search toolbar of firefox it always redirects to search.sidecubes instead of Google.
same issue is also happening in google chrome
I'm not sure your question is well suited for SO. Anyway, Mozilla SUMO has a nice support guide about how to deal with malware on Firefox.
Some suggestions extracted from that page: