The values for Iexplore seem normal to me - my iexplore uses 11 MB <u>per window</u> when I open it with a blank page. Bit of a bloaty piece of crap

I don't actually use it to browse, so I can't say for certain if it climbs that high under normal usage.
I'm more concerned with the BackWeb-randomnumber entry in there, looks like spyware for all I know. Like Raine said earlier, do a full virus check/adware check/spyware check, since it's possible that that's the cause.
Also, if possible, go to Start > Run > type "msconfig" and click OK > Startup tab, and give a list of every command in there and post it here. Or use several screenshots if it's easier, just make sure none of the text in the Command column is cut off