1.) Click rb: type the following in the search: "Troubleshooting". Click Troubleshooting in the results.
Now click programs in the window that appears. Under media player run the library troubleshooter. After that completes, run the settings troubleshooter. Then run the windows media player DVD troubleshooter.
2.) After those finish, Restart the PC. Now try to open windows media player.
Did that solve the issue?
My Computer
At a glance
Windows 10 ProAMD Ryzen 5 2400G Processor with Radeon RX Ve...G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-P...2047MB NVIDIA GeForce GTX 1060 6GB (EVGA)
No video DVD, No CD? Even not audio CD? Can you boot from a bootable DVD (to test if it works outside WIN7)
Open windows file explorer->click on "computer". Does it show the CD/DVD drive?
My Computer
At a glance
Microsoft Windows 7 Home Premium 64-bits 7601...Intel(R) Core(TM) i3 CPU M 370 @ 2.40GHz4,00 GBATI Mobility Radeon HD 5400 Series
Computer type
Laptop
Computer Manufacturer/Model Number
ACER ASPIRE 5742G
OS
Microsoft Windows 7 Home Premium 64-bits 7601 Multiprocessor Free Service Pack 1
CPU
Intel(R) Core(TM) i3 CPU M 370 @ 2.40GHz
Motherboard
Acer Aspire 5742G
Memory
4,00 GB
Graphics Card(s)
ATI Mobility Radeon HD 5400 Series
Sound Card
(1) AMD High Definition Audio Device (2) Realtek High Defi