Doubt it is .Net framework. But, go to Control Panel -> Windows Updates -> Open -> Installed updates -> Remove all updates on the day it started. (These will show up again when you do a check, and you can install again.
NewCrop interface no big deal.
Try to do things you can control. Still think it is computer related and/or network related. You can't control AC or AC support.
But a Cat6 cable and connect from worst computer to server. Don't have server connected to anything. In the past, you had to use a bidirectional cable to do this. Now, cables are fine for this. If there is an issue with connection, get a cheap 1Gb switch and use it. If speeds are good, then it is network. Start troubleshooting at switch.
Google networking businesses in the area. If possible, look for those with MCITP techs (Microsoft) but maybe doesn't matter.
