Hello Shakil Al Kajem, To remove, install or change a cheme you will have to go Personalisation. There you can change the default looks / themes of your screen.

To change your colors you will have to Right click on desktop then click Personalisation 》 Colors 》 Go To high contrast color setting ( you will find it down the screen of your color window ). Goblin designer. There you can change the colors of your text and such. Now if you want to delete a theme you can Open ThisPC and go to following folder: C: Windows Resources Themes Note! Be carefully to not delete the theme you are using currently. If you want to delete a theme. And you are using it, first change the teme you are using then you can delete it.

To change theme on your computer, RIGHT CLICK on desktop 》 Personalisation 》Themes. There choose your default windows theme, or download more from Microsoft website.

Nice Start orb. Very cool Windows 7 and Windows 8 theme. This is a great one! Stylish artistic and relaxing Windows 7 theme with a rainy background image and a glass UI. Awesome theme design with a nice orb and cool hover effects (blue glow on links). Great glass theme, you will have a choice between solid black background or full glass one. Top Windows 7 Glass Themes: Clear Glass 7 Clear Glass 7 Final Release for Windows 7 (X86) 32 bit & (X64) 64 bit Systems is a really elegenat glass theme. More glass themes like this one please.

Hope that this reply will help your inquiry. Hope my little knowledge of the important things of the universe might help you thru your problems.