I am here in thailand with 15 days on arrival visa, I am holding indian passport, can I get another 15 days by boarder running? , haw many days taking for a work permit and non b visa, can I apply for both in 15 days?

Only certain border crossing have a visa on arrival capability. List of crossing where you can get one: http://www.thaiembassyuk.org.uk/?q=node/48

You would probably be able to get the work permit application done. In order to get the non-b visa you will probably have to return to India. I don't think immigration will do a change of visa status for a visa on arrival.

If you had a job offer, why your future employer doesn't apply for a WP and later on giving you all the papers in order to apply for a Non Immigrant B at a Thai embassy abroad instead of reenter with a VOA ... it makes no sense to me honestly...

I am coming for a interview, company need a direct interview before issuing WP.

Can someone tell me what will happen if I overstay in thailand?

you pay 500 baht every day of overstay, but I don't think is a good way to start...

If you just need a little more time you could apply for a 7 day extension, pay 1900 baht and be given 7 days to leave the country.

I am coming for a interview, company need a direct interview before issuing WP.

Can someone tell me what will happen if I overstay in thailand?

If you are caught by the police on an overstay you will be arrested, taken to the International Detention Centre, fined and deported. You will be kept at the IDC until you can buy a flight back to India.

If you leave at any border with an overstay they will let you leave as long as you pay the 500 / day fine to a maximum of 20,000.

Anyone deported or fined for overstay is not currently blacklisted from returning.