Conditional grey-out and disabling of cells

Hi,
I don't know a thing about VB , can anybody help me in managing my attendance and break sheet?

I've uploaded an excel, what I want?

1). If the value in C6 is PRESENT, then only I should be able to enter the details in respective cells against C6 till U6

2). If anything except PRESENT is selected in C6, all the cells till U6 must be greyed out and disabled.

This practice has to be followed till row 28, and this will be done everyday in a new sheet with the respective date.

Please anyone do the coding for me and make the sheet for me, this might get me a promotion in my company.
Please let me know if any other information is required from me.

I really appreciate the help.

Thank you