这是开发信吧?
I learned about your company from newspaper and wanted to build a business relationship with you sincerely. Our company is one of the biggest computer manufacturer in America and is professional in this field. (XX, xx, they are all our loyal customers.)
Attached is our products' catalog and price form. You can learn more details about our products.
If you are interepsted in our products, please contact us at the address above this email. And I am looking forward to hearing from you soon.
前后加上你的落款,括号里面我觉得你可以例举你们公司比较有名的客户,来证明你们势力雄厚.