I thought you had uninstalled Mcafee? If you did you shouldn't be seeing any of it in task manager. Explorer.exe is Windows Graphical interface. iexplore.exe is Internet explorer. The memory usage by each one dosnt seem excessive to me. Most of the others are Windows processes. Dosnt look like theres much of anything else.
I couldnt tell you if IE 8 would be lighter on resources or not, usually new versions just get more bloated with new releases so I would bet no it wouldnt be lighter on resources. Have you tried FireFox, Chrome or Opera browsers. you can have and use more than one browser
Have you ever defragged your hard drive?
You can get another check for malware online if you want:
ESET online scanner:
http://www.eset.com/onlinescan/
uses Internet Explorer only
check "YES" to accept terms
click start button
allow the ActiveX component to install
click the start button. the Scanner will update.
check both "Remove found threats" and "Scan unwanted applications"
click scan
when done you can find the scan log at:C:\Program Files\EsetOnlineScanner\log.txt
please copy/paste that log in next reply.