Conditional Formatting Sheet Became Heavy why ?

Hi to all,

I am working with a excel sheet which contain some conditional formatting. It reached upto 5 pages and now it became very heavy, due to this my excel application working very slow.

The file size is 2.10 MB i don't think that is very heavy file & i m facing difficulties with that sheet. That sheet scrolling slowly, writing slowly.

Pls tell me any solution.

Thanks,,,,,