How to unprotect version 2.01 of "Professional Basic".

The new Professional Basic uses essentially the same scheme as
the old version. However, now there are two versions of PB, one
for 8087-equipped systems (PB.EXE) and one for non-8087 systems
(PB8.EXE).

Both versions will not run if their serial number is "corrupted".
Here is how to modify the serial numbers without letting the
program find out:

First, copy the program to a blank disk using any convenient
method. Then, using the new copy, NOT the original, perform the
following steps:

A. PB.EXE (8087 version):

Using a "disk snoop/zap" utility such as Norton's SM program,
find the 290th sector of PB.EXE. Move the cursor to offser 379
decimal (17B hex). This is the beginning of a nine digit serial
number. This will be the serial number which you see when you
start the program. Modify this serial number to be anything you
want. However, make sure that you change EXACTLY nine bytes, and
WRITE DOWN what you changed them to.

Now go to sector 370 of PB.EXE and move the cursor to offset 171
decimal (AB hex). This is the encoded (key) serial number. The
method of encoding is as follows: The original "plain text"
serial number is rotated LEFT four bytes and one (1) is added to
each byte.

In order to "correct" this serial number to "match" your new
serial number, you must do the same operation on your new S.N.
For example, if you chose YO HO HO! as your new serial number,
you would proceed as follows:

Start:        YO HO HO!
Rotate:       O HO!YO H

Hex equiv:    4F 20 48 4F 21 59 4F 20 48
Add 1:        50 21 49 50 22 5A 50 21 49

Ascii equiv:  P!IP"ZP!I

So you replace the existing encoded serial number with the bytes
shown above.

For PB8.EXE, the equivalent sectors and offsets are:

Serial number:          Sector 299, offset 97 decimal (61 hex)
Key:                    Sector 380, offset 64 decimal (40 hex)

The procedure for PB8.EXE is identical to that given for PB.EXE.

LET THERE BE SOFTWARE!