Microsoft SQL Server 2008 running slow, 100% RAM/CPU

Hello, We are in need of an expert for Microsoft SQL Server 2008 database we are currently using to run our web based application. Our application is running EXTREMELY slow (pages take up to 45 seconds to load data grids), and we are in need of optimizing and fixing the cause. We are not sure why our SQL Database is running very poor. We have been running this application for over 2 years, and about 3 weeks ago, we believe something happened to our SQL Server, or the database itself. It's running on a dedicated server (Windows Server 2008 64-bit) with 16GB of DDR3 RAM, an Core i7 CPU, and is on Gigabit NIC. We recently upgraded the RAM from 8GB to 16GB to see if it would help and it did NOT help, the 8GB was at 100%, and now that we added an additional 8GB, all 16GB is now at 100%. We also noticed that the performance monitor built into the Windows server console is showing the CPU and RAM both running at 100%, and seems to be pegged at 98-100% constant. We need someone who is an expert at SQL Server and can help us diagnose as well as fix and resolve this issue moving forward. You should have had success at solving this issue in the past. You'll need to: 1. Perform database performance monitoring, tuning and maintenance 2. Perform any tuning to the Windows Server itself to allow SQL run efficiently 3. Identify and close and security/network issues related to the SQL server. 4. Perform required Database updates and best practice configurations 5. Follow up Documentation for (1-4)