Whenever I tried to update my Win 98 SE on PIII 450 PC with 256 MB RAM,I get following error messages :-
The Windows Update software did not update successfully. Below are some suggestions to help you proceed:
You may have clicked No when prompted to accept the Trust Certificate. To allow the Windows Update site software to install, click Yes when presented with the Security Warning dialog box.
Your Internet Explorer security settings may be set too high. To install the updated software and access Windows Update, Internet Explorer security must be set to medium or lower, and active scripting and the download and initialization of ActiveX controls must be enabled.

Even after deleting Temp internet files and iuctl.dll & iuengine.dll nad deleting V4 folder I get error message as
To install items from Windows Update, you must be logged on as an administrator or a member of the Administrators group. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure.

I am the only person using my PC and it has no network
Please help me
Thanks

Try this and see if it helps: In Internet Explorer, go to the Tools menu and click Reset Web Settings if you have that option.

If you can't do that, go to Control Panel, select Internet Options and, when the dialog box opens, go to the Security tab. Highlight the icon for the Internet zone and then click the Default Level button.

Try Windows Update again. Any better? Same error message? Something different?

If it doesn't fix it, could you please confirm what security software you've got installed - any anti-virus software such as Norton Anti-Virus, anti-spyware software such as Spybot Search & Destroy or any firewall software.