Even then, i am worried as to whether this will create a problem during my background verification etc.. if i join companies like Accenture etc. which have a stringent BCC policy.
My friends advised me to reduce my relevant experience to 4+ years and also inform the HR before joining itself.
That is bad advice. Why should you lower your experience level just because the company shut down ? Since you have all the documents, just explain to the employer about your situation and that the company does not exist anymore.
I agree with Deepak Bala. Why you should worry if your previous company closed. If you have any references from that company just provide them along with your documents. If still your new company wants some more proofs then that is their problem. May be to be safer just inform your new employer before you accept their offer and resign from your current job.