Is it save to use Internet Explorer or to enable ActiveX pluggings ?
No. Internet Explorer is very unsafe, because it has many vulnerabilities that allow websites to run malicious code on your PC. Better use Mozilla (http://www.mozilla.org) Allowing ActiveX pluggins means that every website you visit can install software and even device drivers on your PC without a question. Do it on your own risk! The default security settings make IE ask user permission to download ActiveX controls, user decides whether he needs specific control or not, same as with other executables. ActiveX itself is not more dangerous then any other kind of exe-files you download and start from your hard-drive, the risk is absolutely the same.