【正确答案】 Dear Friend,
I am writing to express my sincerest apology to you for making your computer stop working.
A week ago, I borrowed your computer to complete my final paper. Unfortunately, the computer's screen went black just now. I accidentally knocked over my glass when I was searching for a reference book, and water spilled on the keyboard. To make up for the problem, I will bring the computer to a repair store and have it fixed as soon as possible. If necessary, I will compensate for any trouble it may cause.
Once again, I feel so sorry for any inconvenience caused. Please accept my apologies.
Yours sincerely,
Li Ming