Yes, hence eating system resources. They'll be trying to heuristic scan each other and go nuts, among other things. Defrag won't do anything as a clean install will reformat the disk, it's not fragmentation. I'd guess something to do with network share slowdown (disable auto-search for network drives, uninstall windows search 4 as well) but photoshop also loading slow indicates ram, gpu, or hd. Check your SMART readings for the hd and see if it's dying, run memtest, and you could try stressing your gpu to look for errors there with something like Furmark.