If you have a reg key. Following way is much easier. It was posed by a good guy but I do not remember his name,sorry. Of course, you need to use RunOnceEx.cmd if you want to run the exe after rebooting. In my case, I use WPI.
1. I assume you have WinRAR installed on your system. Download the original installer of WinRAR here.
2. Using WinRAR, extract the files of the SFX to an empty folder.
3. Copy your rarreg.key to that folder.
4. Select all files in that folder and select "Add to archive..".
5. In the "General" tab, select Best Compression, Create SFX, Create Solid Archive, Put Authenticity Verification, Put Recovery Record, and Lock Archive.
6. Click the comment tab, and paste this comment.
CODE
Title=WinRAR 3.50B3
Text
{
<html>
<body bgcolor="#ececec">
<style>
body {
color: #000000;
background-color: #ffffff;
font-family: "MS Sans Serif";
font-size: 12;
scrollbar-3dlight-color:#f0f0f0;
scrollbar-arrow-color:#f0f0f0;
scrollbar-darkshadow-color:#909090;
scrollbar-face-color:#909090;
scrollbar-highlight-color:#f0f0f0;
scrollbar-shadow-color:#f0f0f0
}
em {color: navy; font-style: normal}
</style>
<b>WinRAR is a powerful archiver</b>. It
provides complete support of <em><b>RAR</b></em> and
<em><b>ZIP</b></em> files, unpacks <em>7Z</em>, <em>ACE</em>,
<em>ARJ</em>, <em>BZ2</em>, <em>CAB</em>, <em>GZ</em>,
<em>ISO</em>, <em>JAR</em>, <em>LZH</em>, <em>TAR</em>,
<em>UUE</em>, <em>Z</em>. Among WinRAR features are strong compression,
volumes, encryption, self-extracting modules, backup
facilities.<br><br>
<b>WinRAR is shareware</b>. Anyone may use
it during a test period of 40 days. Following this test
period or less, if you wish to continue to use WinRAR,
you must register.<br><br>
<b>There are no additional license fees</b>, apart from
the cost of registration, associated with the creation
and distribution of RAR archives or self-extracting
archives. Legally registered owners may use their copies
of WinRAR to produce and distribute those archives free of
any additional RAR royalties.<br><br>
<b>WinRAR archiver is distributed as is</b>.
No warranty of any kind is expressed or implied. You use at your
own risk. Neither the author nor the agents of the author will be
liable for data loss, damages, loss of profits or any other kind
of loss while using or misusing this software.
</body>
</html>
}
Path=WinRAR
SavePath
Overwrite=1
Delete=*.lng
Delete=rarlng.dll
Delete=rarext.dll
Delete=register.frm
Delete=rar_site.txt
Delete=register.txt
Delete=order.txt
Delete=Dos.sfx
Delete=os2.sfx
Delete=Formats\ace.fmt
Delete=Formats\arj.fmt
Delete=Formats\cab.fmt
Delete=Formats\gz.fmt
Delete=Formats\lzh.fmt
Delete=Formats\tar.fmt
Delete=Formats\uue.fmt
Delete=Formats\bz2.fmt
Delete=Formats\iso.fmt
Delete=Formats\unacev2.dll
Delete=Formats\7z.fmt
Delete=Formats\7za.dll
Delete=Formats\z.fmt
Presetup=uninstall.exe /clean
Setup=uninstall.exe /setup
7. And the most important part, click "OK"