This paper describes the methods and means used for creating a computer cluster using ordinary PCs. The cluster is running a replicated relational database, and two custom Web applications, used as the database clients. Operating system running all this is Linux 2.4, with Linux Virtual Server (LVS) used as the load-balancing solution, MySQL 4.0 as the replicated database (supporting transactions and referential integrity), and Apache 1.3 as the Web server. PHP4 is used for Web applications development. Additionally, a High Performance Computing (HPC) cluster is implemented using OpenMOSIX. Measurement and comparison of achieved performance levels is done as the final aim, using two custom applications developed for that purpose, acting as clients of two deployed Web applications. Performance-measurement applications are running under Microsoft Windows, and are developed using Borland Delphi 7.