Lost Power abruptly and now explorer.exe hangs

So, the story so far. On Christmas eve got a brown out and the computer shut down abruptly. On a reboot the system seemed ok until I tried to access some files and explorer.exe started to hang, other programs started to hang as well, like Chrome, Firefox, etc. So I ran all sorts of tests, chkdsk /f on the C: drive, sfc /scannow , Western Digital's Data Lifeguard on the C: drive (It's a Western Digital drive), etc and no errors found. So I reinstalled Windows 7, after some drama with Windows Update (got that fixed thanks to you guys) I got the system to update finally, started to access the back up files and bam! explorer.exe froze solid for several minutes repeatedly. So once more into the breach this time using Seatools to test all four drives (1 boot, 3 data, 2 WD and 2 Seagate) to see if any of them were failing. Nothing, all four passed an extended test. Don't hear any of them clicking and when it's frozen the drive activity light only flickers on occasion like normal. The last time I had a drive puke the activity light went ballistic and the drive clicked. This time, none of that. So I don't know, this is a fresh install, I backed up and formatted the boot drive before installing Windows 7 again. Anyone might know what is causing explorer.exe to freak out and lock up my system for minutes at a time?

Win updates can use a lot of resources.
Try to disable it on services - %windir%\system32\services.msc

It was before I reinstalled that it started to do this then after a reinstalling Windows 7 and there were no more important updates were left.

I have had that issue and man it's a nightmare... first it was a failing hard drive and then it was a failing PSU. Replaced them both and the hangs went away.

I too ran every single test and checked drive health and everything said my system was ok. No errors. When the hard drive fails your system will check for inconsistencies deleting corruptions and recovering orphaned files after only a few normal reboots. Things stop working, errors everywhere.

When the PSU was failing my system would hang, I'd get bsod about memory management, and random restarts where my boot order was screwed up. BOOTMGR MISSING. Please insert a bootable device. blah blah blah.

So the tests won't tell me which drive is failing? >.< Oy! Ok. So it's down to elimination rounds, power down, pull the data cable boot up, and access the files and see if it freezes, if so, repeat until the drive is found? Then for certainty swap the data cable and recheck. Right?

yeah disconnect drives one at a time. in this instance though it was my psu. i upgraded today from 850 to 1000 watts then plugged in my suspected failing drive and nothings gone wrong yet. i think i was just demanding too much power and the drives couldnt get enough.

I'll check that once I figure out where my DMM went. >.<

Update, it took a *lot* longer but while playing Minecraft (for the third time in nearly two days) it eventually locked up, Chrome couldn't connect to the web, and for the giggles I tried File Explorer and it was locked. So, again, for the giggles, I ran MemTest86 overnight, nearly two passes and no errors. So I am back to square one. Not drives, though just unplugging the data cable (not power, the drive is still powered up) on the 4tb hdd helps. So far I've reinstalled Win 7 about three times, downloaded all available drivers from the web, so drivers are all up to date. Thanks to you guys the updates from Microsoft are all installed. I've unplugged just the data cables (not power, just so it's pulling the same amount of power) from all four drives, reinstalled Windows 7 onto a lightly used data drive for when I pulled the current primary drive. Tested memory. Tested the power supply, well, the +12 and +5 volt drive rails, the DMM's probes are too big to back probe the 24 pin ATX connector, and that tested fine. So I am at a loss. What next? O.o

Have you checked your event viewer logs?