The voltages in a network cable are minute but stable power has to come from somewhere - the rebooting is a very good sign the PSU is on it's way out. Before you get a new one, take a look at some of the suggestions here click here
Thanks again. The article identifies cable temrination and router as poss causes, but both of these are fine because the cable works on another machine via the router. Indicating that cable and router can take a 30m. I have got the 20m to work on the win98 (but is is grey and needs to be white!) . But I think some of the difficulty is that I may have an intermitten fault, possibly adding further evidence that my problem, as you suggested, is a failing PSU.
If this is so, I think I may be stuffed coz the win98 pc is a dell and I suspect they use propriatry (?) PSUs, am I right?
The rebooting problem was caused by was goback playing up.
I bought a 20 m cable from maplins. It works with the win98. But I can't run grey cable around the house. It looks awful. Anyway, perhaps the psu is not the problem.
Well I gave up and handed the problem to my local computer shop. Their only suggestion is to sell me a usb adapter. But what little I've read of usb adapters suggests that they a very slow.I have a very fast broadband connection.
Anyone got any further thoughts about why a working 20 metre cable cannot work with a working win98 dell computer?