Windows 7: BSOD error not detectable by microsoft security essentials

Hi,

I recently purchased a lenovo laptop for home purpose around 1.5 months back. The laptop was having already microsoft security essentials (MSE) and mcafee antivirus plus software. Unfortunately, yesterday i was facing blue screen on death type of error (BSOD) error. On one forum, I found that it may be due to the mcafee antivirus software. So, I uninstalled the software as per suggestion.
My questions is :
Why MSE was not able to detect this bsod error ?
Moreover, why mcafee, which itself is a anti-virus software, was causing this issue?
Please help to know the exact issues in detail.

Morever, I want to install good free antivirus software. I am totally confused whether should I install the antivirus software or, the internet security software. Please throw more light on good free internet security software from longer perspective. (I just found that almost all free trials are only for 1 month only)? Moreover, why built-in windows firewall and microsoft security essentials (MSE) are not enough for detecting malacious software. Why extra internet security software or antivirus software is required ?



Thanks,
Ashish

BSOD analysts - please see this for some background and ground covered:
microsoft security essentials

All you need is Microsoft Security Essentials & Malwarebytes

MSE does not detect BSOD!! However having 2 anti virus will probably give you a BSOD

Head over here if you still get BSOD: http://www.sevenforums.com/crashes-debugging/

I found on microsoft website about a utility named as Microsoft Malicious Software Removal Tool
. So is this utility good or bad compared to malwarebytes's anti-malware ?