How we disable or enable particular cell, sheet in excel

By disable I assume you mean "make it so it can't be edited in any way." This is called "locking a cell" in Excel lingo. If this isn't what you mean you will have to correct me, I will answer as if my guess is correct.

By default, ALL the cells are locked. You have to turn on "locking" on a sheet by sheet basis to make this locking effective.

Click on TOOLS > PROTECTIONS

There are several options in here to do what you want.

Protect Sheet
Along with adding a password only you know, this effectively only allows you or anyone else to edit data in UNLOCKED cells. By default, all cells are locked.

(To unlock a cell prior to turning on a password for the sheet: Highlight the cell(s) you want them to be able to still edit/type in, then use the FORMAT>>CELLS>>PROTECTION and uncheck the "locked" box.)

Allow Users to Edit Ranges
Allows you to enter and give a name/password to specific ranges of cells within the sheet. This is a way to allow some edits without unlocking those cells.

Protect Workbook
Instead of activating security on a single sheet in the workbook, you can lock down the whole workbook.

Does this give you what you need? You will have to go in and play with the FORMAT > CELLS > PROTECTION > Locked and the protection features to see how it effects your access to your worksheets, but I do this all the time, works great!