Well, the long and short of it is that Internet Explorer has an extremely large number of security vulnerabilities that are routinely exploited to install spyware and other unwanted garbage onto people's computers. Which is why I recommend that people use it only as a last resort, and as sparingly as possible.
The main issue with Internet Explorer is ActiveX. In grand Microsoft tradition, it was a fantastic idea that was implemented so badly that it just boggles the mind. The problems with ActiveX are three fold. First, it's compiled code, so it's really not much different from any other program you run on your computer. Second, is the way Microsoft integrated the web browser into the operating system... None of which would be so bad if not for the third issue, in that Microsoft's development mentality is still stuck in the pre-Internet days when you didn't have to worry much about whether programs are remotely exploitable. Microsoft's usual development strategy is just to jam in as many new features as possible to every new version of a program. So, think of it like trying to write a couple million page research paper, full of references, foot notes, annotations, etc, and never once make a spelling, punctuation, citation, or any other kind of error. It's just not realistic.
Flock, and other browsers that aren't based on IE, have a number of things going for them. One is that they run like any other program, so it's much harder for them to trigger a total system compromise like IE can. Second, is that they have learned from Microsoft's many follies. Third, is that they were developed by companies that sprang up during the Internet age, so they don't have the same every computer is an island unto itself mentality Microsoft still does.
If I were to speculate a bit, I would say that Gates leaving Microsoft is the first step in a new renaissance for Microsoft. Once Ballmer is likely ousted for his rather unimpressive time at the helm of the company, and most of the "old guard" is gone... I suspect Microsoft will once again become a company known for putting out quality products at a reasonable price. They won't have to resort to illegal market manipulation techniques to prop up their products, they will be able to compete on merits.
Anyay to deal with some of the issues of your other post. Any time you're wondering about some program, type the name into Google and see what turns up. That should give you a good idea of whether or not it's a scam program or not.
I will let the die-hard IE fans who seem to enjoy living with the constant threat of malware explain the process of getting rid of the malware you've already picked up. What I will do, is share with you my rather simple method of avoiding these problems in the future.
TIPS FOR A SMOOTH RUNNING SYSTEM
The more of these suggestions you follow, the fewer problems you should have. Follow them all, and you've probably eliminated at least 95% of all potential problem sources.
Things you should NOT do
1: Use Internet Explorer
2: Use any browser based on Internet Explorer
3: Use Outlook or Outlook Express
4: Open email attachments you haven't manually scanned with your virus scanner
5: Open email attachments you were not expecting, no matter who they appear to be from
6: Respond to spam messages, including using unsubscribe links
7: Visit questionable websites (e.g. porn, warez, hacking)
8: Poke unnecessary holes in your firewall by clicking "Allow" every time some program requests access to the Internet
9: Click directly on links in email messages
10: Use file sharing or P2P programs
11: Use pirated programs
Things you SHOULD do
1: Use a non-IE or IE based browser
2: Always have an up to date virus scanner running
3: Always have a firewall running
4: Install all the latest security updates (the exception to the no-IE rule)
5: Delete all unsolicited emails containing attachments without reading
6: Manually scan all email attachments with your virus scanner, regardless of whether it's supposed to be done automatically
7: Copy and paste URLs from email messages into your web browser
8: Inspect links copied and pasted into your web browser to ensure they don't seem to contain a second/different address