Which Windows version?
Which IDE version?
Which boards? If applicable (Uno, Mega, Nano), for each board, can you identify the TTL-to-USB converter? Common options as the 16U2 (square chip, legs at all sides) and the CH340 (rectangular chip, legs at two sides). If accessible, right click the device in Windows device manager and click properties; it will probably tell you what TTL-to-USB converter is used. Post it here. You can also go to the details tab, select hardware IDs and post the VID and PID.
It might very well be a CH340; verify using above. If so, download CH341SER.zip from CH341SER.ZIP - Nanjing Qinheng Microelectronics Co., Ltd., extract it and run the executable.