Video issues with Windows 10

It could be the overscan is not set up properly. Have you installed the latest Catalyst package from AMD?

For some bizarre reason, the drivers default to overscan, which leaves the black borders on the edges of the image.

Check display resolution is set to the appropriate recommended or native resolution (consult the monitor specs), using this guide:

How to Change Screen Resolution of Displays

There is no Windows 10 driver from AMD as the HD 3450 is now considered legacy, the latest driver from AMD is for Windows 8.  But there appear to be some drivers for Windows 10 available through Windows Update for the Radeon HD 3450.  You can get recommended drivers from Windows Update by using these options:

Update drivers in Windows 10

If neither of those work, have you tried the monitor's screen adjustment controls to expand the horizontal and vertical edges of the display?

WDDM 1.0 = Vista, WDDM 1.1 = Windows 7.  AMD recommends using the drivers available from Windows Update for HD 4000, 3000, and 2000 products running Windows 10:

https://community.amd.com/docs/DOC-1311

An alternative is a new budget video card.

You cannot use the latest drivers with HD2000 HD3000 HD4000 series cards.

You can only use WDDM 1.1 Vista Drivers aka LEGACY Catalyst 13 Drivers.

http://support.amd.com/en-us/download/desktop/legacy?product=legacy2&os=Windows%208%20-%2064

AMD Does not differentiate for the legacy drivers.  Thats why they list them as VISTA or WIN7 compatible.

http://support.amd.com/en-us/download/desktop/legacy?product=legacy2&os=Windows%208%20-%2064

 http://support.amd.com/en-us/download/desktop/legacy?product=legacy2&os=Windows%208%20-%2032

Direct Linking however does not usually work.

https://www2.ati.com/drivers/legacy/13-1-legacy_vista_win7_win8_64_dd_ccc.exe

One of the limitations of WDDM driver model version 1.0 is that it does not support multiple drivers in a multi-adapter, multi-monitor setup. If a multi-monitor system has more than one graphics adapter powering t
he monitors, both the adaptors must use the same WDDM driver. If more than one driver is used,  Windows will disable one of them. WDDM 1.1 does not have this limitation.Directx June 2010 has DX9 and DX10 drivers.

WDDM 1.1 drivers are backward compatible with WDDM 1.0 specification; both 1.0 and 1.1 drivers can be used in Windows Vista with or without the Platform Update

Recommended for older cards and drivers.

This means you can reintroduce the older driver set from XP all the way to windows 10.   DOTNET and other components will also need to be reinstalled.

 IN 7 8 and 10 you use control panel to RE enable Legacy Direct play and DOTNET 2.0 and 3.5.

ATI ccc is a DOTNET application.

XDDM 1.0 is Directx9.0 aka XP  circa 2002

WDDM 1.0 1.1 is Directx 10 aka VISTA circa 2007

WDDM 1.2 is directx 11 aka WIN7 circa 2009

WDDM 1.3 is directx 11.1 aka win8 circa 2012

WDDM 2.0 is directx 12 aka WIN10 circa 2015