installing Win98 over a Japanese version

[sallam]

I dont know if someone could help me in this:
I just bought a used NEC VersaPro NX VA23C notebook from Japan. The OS installed is Win98 Japanese version.

I'm trying to install an English version of Win98 over it, from Windows, but I get this error:
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setup error:windows character set mismatch
setup has dctected an incompatible windows character set. setup can not proceed!
you have to install windows into a clean directory press any key to continue
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So I reformatted, and installed afresh. This was a drawback, because this notebook looks like it had some nice tools installed, making the performance quite speedy, much than is expected from its specs (P233, 32mb ram). Also the power button does not do a soft-off like it does when it was before formatting. So I swithed back (luckily I use Ghost).

So, is there a way to install the English version over the current Japanese one, without having to format and loose all the useful installed tools?