Can B visa holder convert to F or other status?

While it is permissible to change from one status to another from within U.S., it may not always be advisable.

Typically, when someone enters the U.S., supposedly for a short visit (e.g. B-1 or B-2) and then tries to change it to a longer term visa (F-1, L-1, H-1, etc.), USCIS often frowns upon it (and may not grant it), but the consulates invariably frown upon it. My recommendation in most of these cases is to avoid this type of change. If you have already obtained the change, it may be very difficult to procure a visa whenever you need to travel abroad.

While it is permissible to change from one status to another from within U.S., it may not always be advisable.

Typically, when someone enters the U.S., supposedly for a short visit (e.g. B-1 or B-2) and then tries to change it to a longer term visa (F-1, L-1, H-1, etc.), USCIS often frowns upon it (and may not grant it), but the consulates invariably frown upon it. My recommendation in most of these cases is to avoid this type of change. If you have already obtained the change, it may be very difficult to procure a visa whenever you need to travel abroad.

In April 2002, INS changed its regulations regarding B to F-1 or M-1 (students) status conversions for people who enter USA from then on. INS maintains that B to F-1/M -1conversions from within USA will be permitted only if at the time of entering the USA (for instance at the airport) the applicant expressly declares to INS his/her intent to change to F-1/M-1 status. AS A PRACTICAL MATTER, HOWEVER, CIS seems to have often given changes from B to F status ignoring its own regulations. But in these cases also, the visa problem from consulates will remain.

The better thing to do is to go back to your home country and try for a visa there. Chances of getting a second visa are better if you have done nothing to violate the terms of an earlier visa.