The query is not drafted properly so as to indicate what exactly do you want.
However:
1. If the company that employed you has been taken over then if you have not accepted any chagneg in service conditions then you need to issue notice of resignation as per notice period inserted in appointment letter issued to you.
The management can not accept notice of resignation before expiry of notice period/LWD issued by you.
If the management issues LWD before expiry of notice period tendered by you nit has to tender notice pay for shortfall in notice period, subject to acceptance by you.
2. The notice period is part of service conditions and is governed by various enactments that apply to establishment/employee. An able Labor Law Consultant can update you on it.
3. You must get offer letter with date as next date from LWD in past employer so as to avoid any break in service.................................and flexibility to join on the strength of copy of notice of resignation alone as employee can't supply service certificate,relieving letter,FnF statement,salary slips,Form16 etc until these are supplied by employer to employee.
4. You may download all tasks perfromed,perfromance date,appreciations,awards,rewards etc and also that NO tasks are pending at your end.
Build rapport with Boss and apply your skills to get relieved at a happy note.
If no stinkers and SCN was ever issued to you then you may have valid points to contest adverse comments in reliving letter/BGV etc.
If you are unable to handle on your own entrust to your counsel.