Watching Blu-Ray video is difficult when the image is not stable.

Here are the specifications for the video I watched in Media Player Classic:

General
ID: 7 (0x7)
Complete name: J:\Digi-box\Snooker - Gibraltar Open.ts
Format: BDAV
Format / Info: Blu-ray Video
File size: 8.32 GiB
Duration: 2 h 10 min
Overall bit rate mode: Variable
Overall bit rate: 9,096 kbps
FileExtension_Invalid: m2ts mts ssif

Video
ID: 610 (0x262)
Menu ID: 607 (0x25F)
Format: AVC
Format / Info: Advanced Video Codec
Format profile: High @ L4
Format settings: CABAC / 4 Ref Frames
Format settings, CABAC: Yes
Format settings, Reference fra: 4 frames
Format settings, GOP: M = 4, N = 32
Codec ID: 27
Duration: 2 h 10 min
Bit rate: 8,343 kbps
Maximum bit rate: 3,156 kbps
Width: 1,920 pixels
Height: 1,080 pixels
Display aspect ratio: 16: 9
Frame rate: 25,000 FPS
Standard: Component
Color space: YUV
Chroma subsampling: 4: 2: 0
Bit depth: 8 bits
Scan type: MBAFF
Scan type, store method: Interleaved fields
Scan order: Top Field First
Bits / (Pixel * Frame): 0.161
Stream size: 7.63 GiB (92%)
Color range: Limited
Color primaries: BT.709
Transfer characteristics: BT.709
Matrix coefficients: BT.709

Audio
ID: 611 (0x263)
Menu ID: 607 (0x25F)
Format: MPEG Audio
Format version: Version 1
Format profile: Layer 2
Codec ID: 3
Duration: 2 h 10 min
Bit rate mode: Constant
Bit rate: 384 kbps
Channel (s): 2 channels
Sampling rate: 48.0 kHz
Frame rate: 41,667 FPS (1152 SPF)
Compression mode: Lossy
Relative to video: -797 ms
Stream size: 360 MiB (4%)
Language: Finnish

Menu
ID: 6703 (0x1A2F)
Menu ID: 607 (0x25F)
Format: AVC / MPEG Audio
Duration: 2 h 10 min
List: 610 (0x262) (AVC) / 611 (0x263) (MPEG Audio, English)
Language: / Finnish

I used to be able to watch Blu-Ray videos, but I no longer know / remember which settings I need to choose in order to watch Blu-Ray recordings.
What do I need to do to make this possible?

You don't need any special settings. All I can suggest is to do a fresh installation.

I can't help without more details about your system and what actually goes wrong. "not stable" is not a useful description of a problem.