There's a couple of ways that a technician can connect and take remote control of your PC
Here's a list of a couple of APPS that can be used.
TeamViewer
TeamViewer v13.
TeamViewer is easily the best freeware remote
access software I've ever used. There are tons of features, which is always
great, but it's also extremely easy to install. No changes to router or
firewall configurations are needed.
Remote Utilities
Remote Utilities Viewer.
Remote Utilities is a free remote access program with some
really great features. It works by pairing two remote computers together with
what they call an "Internet ID." You can control a total of 10 PCs
with Remote Utilities.
Unfortunately, configuring Remote Utilities can be confusing
on the host computer since there are lots of different options.
Remote Utilities can be installed on Windows 10, 8, 7,
Vista, and XP, as well as Windows Server 2012, 2008, and 2003.
UltraVNC
UltraVNC. © UltraVNC
Another remote access program is UltraVNC. UltraVNC works a
bit like Remote Utilities, where a server and viewer is
installed on two PCs, and the viewer is used to control the server.
AeroAdmin
AeroAdmin.
AeroAdmin is probably the easiest program
to use for free remote access. There are hardly any settings, and everything is
quick and to the point, which is perfect for spontaneous support.