OK, so I've gone through all the steps in BC's "Slow Computer Checklist" - including scanning in safe mode for malware with half a dozen different programmes - but failed to spot any malware.
Apart from painfully slow running right from the log-on screen, along with massive memory consumption by Firefox (FF) or Internet Explorer (IE) web-browsers, the main problem is that FF has suddenly started opening up an extra window whenever it takes me to a website that I have hyperlinked in a MS Word document. The first window is the one that I need. The second window contains a message that the page could not be found while the address bar has the URL appended by this: "FirefoxHTML\shell\open\command".
If i use IE as the default web browser for my hyperlinks, the problem is even worse (but no message about shell\open\command), including a Windows message that IE is being closed to prevent "data execution".
As I need to access over 600 webpages every week for research purposes, this is a huge waste of both my time and my computer's memory.
WHAT I'VE DONE I've tried sorting this out with the Firefox support people but without sucess - see this link: https://support.mozilla.com/en-US/questions/749218
I came across this article: http://antivirus.about.com/od/windowsbasics/a/shellopen.htm and it seems to indicate that malware might have corrupted the default values of at leats two of my registry keys. But I'm reluctant to mess with the registry without further guidance.
Can anyone help?