'silver',
Ok, forgive me or please allow me but, I can't hold back, I have to throw my 2 cents worth in on this one; I state it thusly cus what the others have (already) said is spot on.
I deal w/ clients all the time that don't know what to update or not, what to download or not. There's no denying, finding info & know there are questions to ask and what those are, make things tough... certainly (most) retailers don't tell buyers much. That said, here's the basic rule or thumb...
KEEP UP TO DATE!
Applies to the following:
Microsoft/Windows Updates - ALL Importants or Criticals. (this is not open for debate)
Most Optionals are not required, hence the name but, it's best to ask someone in the know.
By the way, most Updates are security related, a few are functionality. Ergo, NOT doing them leaves one vunerable to security risks.
Microsoft Security Essentials basically looks after itself.
Please note!... The Auto Updates only apply to the Criticals, not the Optionals. And MS Updates & what MSE does (to protect your system) by default happen @ 2 & 3 AM. The machine cannot be powered off for these things to happen (by themselves); can be "Asleep" but, not OFF. Otherwise, you have to change the default times or (remember to) do everything manually.
Java
Adobe
CCleaner (versions)
Browsers
And
Malwarebytes should be updated before it's run.
Now, speaking of browsers... yes, it's absolutely true, as the other 2 said, IE9 is FAR superior to IE8. BUT, you never mentioned IE8, you only said you are not running IE9. I can't tell if you are (STILL) running IE8 OR if you are using some other browser than Internet Explorer. Be that as it may, I will be a lot more blunt & bold enough to say, you should be using IE9... simply because it is arguably the best browser currently available.
On the heels of a comment Ted made... This is a comment of mine, taken from a thread in the Microsoft Windows 7 IT Pro Forum where I, also, write...
There are certain basics & best practices that must be met or exist... being/keeping current, good A-V, good A-M, good firewall, only good surfing & downloading activity et al, absolute 'givens' AND correct, NO platform, NO Operating System, on the Net, is immune or untouchable & yes, the misconception came from when some things had small footprints & sickos & criminals didn't give those much attention. But, beyond the 'givens', the biggest threat & weakness regarding security is the (all too often & sadly naive, unaware or even thoughtless) user. Somehow the messages of prudence just don't get to most users. End Users must know there are concerns to have, required tools to have & schedules to keep but, DO they know to even ask the questions or have the cares OR what to do if they did?? The single biggest, indullable, most challenging "Security Risk" & hardest to mitigate against OR educate is computer Users.
And lastly I urge to to read & keep (for future reference) the following, Link Removed
Regards,
Drew