Thanks all, for your informative replies.
@Liverpool_fan : This is what I thought exactly, we got same thinking. But i dropped the idea thinking that for this I would have to install some local web host(if m correct) like apache etc. with PHP and MySQL. This won't do good.
@Garbage : I believe C#/
VB .net requires .net framework installed too. Tell me if I am wrong. About moving them to linux. Its not about just one company. I would be making this software for a company which would be sold to thousands of its customers as a new and improved version of there old software. Meaning, Linux on all of those thousand customers.
@lucifer_is_back : does C# requires any base application or runtime environment?
@all : There previous software was made on DBASE(if you all know). They used simple codes similar to fox-pro which was used to access .dbf files, saved it to .prg files compiled to executables. Its was simple, flexible, efficient but lags because of being DOS based. I need to make it GUI based with same features. I am loosing my time, help me soon!!
Thankyou!!