Some usefull Link for OOPS

1. OOPS Part I
http://www.c-sharpcorner.com/Code/2005/June/OOPSand.NET1.asp
2. OOPS Part II

http://www.c-sharpcorner.com/Code/2005/June/OOPSand.NET2.asp

Improving .NET Application Performance .This Link Gives you a Wonderfull Document from Microsoft .
http://www.microsoft.com/downloads/details.aspx?familyid=8A2E454D-F30E-4E72-B531-75384A0F1C47&displaylang=en

The main impact on Performance and Scalalility of the .Net application are

Memory Misuse
Resource Cleanup
Improper use of threads
Abusing shared resources
Type Conversions
Misuse of Collections
Inefficeient Loops

Use full link to prepare for Interview .NET FAQ http://www.codeproject.com/useritems/dotnetinterviews.asp