Win 7 is bogging down

[unfaithfulsfan]

I'm not sure exactly what's going on. About 3 months ago I did a fresh install of Win 7 to get rid of some lingering remnants of a toolbar/malware problem my better half inadvertently installed which nothing would remove completely.

Over about the last month, my machine has progressively gotten slower & slower & slower. My first thought was an app I installed but in following that lead I cannot find any unusual resource hogs. In looking at Task Manager, explorer.exe is using the most resources at this moment nearly 3GB of RAM and the CPU is at 100%. There are also two instances of explorer.exe along with five or six instances of Chrome although I have only one tab open.

I'm trying to kill off as many processes as I can to see if anything turns loose of the CPU but so far nothing has helped. I'm going to have to kill the main explorer.exe to try to free everything up but I'd better post this before I do that.

So, as usual, any suggestions or input will be greatly appreciated.

Update--------------------------------------------------------------

As it turned out the instance of explorer.exe that is eating up nearly half my available memory (3.7 GB as of a minute ago) can't be ended. The other explorer is the "real" one that can be ended.

I saw another post on MSoft's answer site that mentioned if you change the default paths for Libraries (which I have done for a couple of years now) it can cause the system to hang but there was no real elaboration so I don't know whether that's true. I've not noticed this problem since the time I've changed the Libraries to other drives.

I bought a laptop on eBay that I'm going to have to reload 8.1 so just to see what would happen I temporarily threw it on another partition on my desktop. Everything just screams so I think I'm just going to blow it all away and try again.