My 6 year of H1B are already finished and I am transferring my visa to L2 as my wife is on L1, can I still work on L2?

You should be eligible to stay and work so long as your spouse maintains her L-1 status. Green card application can also run parallel to these.

I'm engaged to a US Citzen. I'm from the UK. I've been living in the US on an 01 visa. My visa expires at the end of feb 2014.

If you wish to marry and continue living in the U.S., filing a one-step IR petition will be the best route. Once filed, you are eligible for EAD...

It is valid until it is voided by the Consulate.

Received EAD, one week after H1 start date (previous status H4). Do we need to run pay roll for one week to be on valid status

Are you the company seeking this query or the candidate?

H1B denied - want to switch to F1

With the end of OPT and denial of H-1B, your status ended. If you wish to go back to school, you will get a new I-20 and then re-enter in F-1 status.

H1b visa is still in pending. Can I come to USA with F1 visa and then work on H1B. How USCIS works in this case?

If you enter on F-1, the requirement is to go to school to study. Unless you are authorized, you cannot work on F-1. If the intention is to join...

Will the time period of my first visit to usa counted for30/60 day rule applicable for marriage on tourist B1visa? Thanks

It is best to seek a confidential consultation and retain a lawyer towards your filings should you decide to apply for AOS.

H1 to H4 conversion - visiting home country

File I-539. In home country apply for H-4 visa to return to the U.S. on H-4.

H4 Withdrawal - Advise Required

Your status changes to H-4 upon approval of the petition. The employer will have to seek COS in your behalf.

H1B visa extension after 6 years by company B based on approved I140 which has been filed by company A?

Only if Company A will keep their I-140 and offer your future employment.