Unofficial Windows 98 Second Edition Service Pack 3.64

Before installing U98SESP3.EXE make sure that:
1/ You have the original w98SE installation disc.
It will change core system files. It means that if something goes wrong you must be prepared to reinstall windows from the beginning.
Sometimes installing U98SESP3.EXE after a fresh install is working normaly while it failed on an old install.
2/ You made a back up of all important datas.
It's extremely unlikely that an error forces you to reinstall windows and eventualy to reformat thus to erase your hard drive.
But for the sake of safety, please do it!
3/ You made a back up of your system files
A copy of the "windows" and "Program Files" directories, at least the "windows" directory, preferably on a second physical hard drive or on CD or DVD or an external drive.
This is usefull to revert back to a prior w98se install which was already updated and functioning well.
Restoring windows 98 can be done simply be recopying all the system files back to their original location, in dos mode. The easiest way is to use a second physical (not a partition) and internal (not USB) hard drive.
It's aslo a good idea to make sure a copy of the registry has been automaticaly preserved in the system files you backed up and to know how to restore the registry in dos: boot in DOS, then type SCANREG /RESTORE. 
4/ You have time and patience to read all the instructions
If you are somebody who will select all options no matter what they are or who will click "OK" instead of "Cancel" on any dialog box without knowing what was the question about, then you are sure to run into trouble.
Don't do it in a rush. If words are written on the screen it must be important. Please read them.
5/ You have read the disclaimer below.

Disclaimer:

The author and owner of this website as well as the owner of the server hosting this website and all the persons having been involved in the creation or the distribution of the files, updates and executables present on this website will not be responsible for any material damage, loss of hardware performance or functionality, alteration or loss of datas, theft of datas, exposure of classified documents, loss of privacy, penalty, material or financial depreciation or loss or liability or any other loss or damage or liability of any kind caused by the use or inability to use these files, updates or executables.

They are delivered to You for free, as is and without any warranty attached beyond those already described in the agreements between You and their authors or vendors if any. You understand that most of them doesn't come with any warranty at all and that there is no garantee that they will work on your computer as advertised.
Moreover you agree to use each of them with respect to the user agreement provided by their author if any.

Use at you own risk.

More specificaly, You understand that the author and the other persons who participate in its creation, promote, advice to use, or distribute the Unofficial Windows 98SE service pack (U98SESP3) known as U98SESP3 or as U98SESP3.EXE or any other denomination used for translated versions or further updated versions, as well as Microsoft Corporation or any other party directly or indirectly concerned will not be liable for any damage, loss of software or hardware functionality or performance, loss of datas, loss of time, loss of money or any loss or liability of any kind caused by the use or inability to use U98SESP3.

You understand that U98SESP3 is not a product of Microsoft Corporation and not a product of a commercial company, that's it's developed and distributed as is, benevolently, unofficialy (althought legaly) and freely without any guarantee attached, without any promise of support, that there is no guarantee whatsoever that it will work as advertised and that you use it at your own risk and in full consciouseness of the risks attached to an unofficial service pack for an operating system.

Before installing U98SESP3 You are supposed to have made all the necessary steps to saveguard your datas and be able to reinstall an operating system as described in, but no exclusively the important notice above and to have the technical knowledge and ability to fix computer related problems in the case U98SESP3 will prevent your computer to work properly.
These necessary steps consist in, but no exclusively:
- Having the original w98SE installation disc
- Makiing a back up of all important datas
- Making a back up of the system files
- Having a back up of the registry

Before, during and after the installation you are supposed to read CAREFULY all the instructions you get through dialog box messages, dos prompt messages or otherwise.
You are also supposed to understand these instructions and have the appropriate knowledge to act accordingly and to select the appropriate options if any.

U98SESP3 and all other versions or translations of it are distributed for free, without any profit for the author(s) and for the distributors.
U98SESP3 cannot be distributed in exchange for money or any other liability.
You have the right to distribute U98SESP3 to the legaly binding conditions that you do not charge any amount of money or make any profit directly or indirectly, that you distribute an unmodified version and always the latest version available on this website or from the author's website if any.