45 second delay in webpage download

[chris sanctuary]

Dear Forum,
When clicking on links or entering target web addresses I experience either virtually immediate response (as indicated by the 'connected' icon at bottom right of W98 screen) or an unwanted long delay (about 45 secs at present).
I do not think the explanation is 'local cache versus true download' since then I would expect a range of delays for true download depending on traffic intensity in the network.
There is no problem in physical dial up itself - it is with page access once connected.
I think it first occurred after I installed firewall ZoneAlarm (plus PestControl).
Before that, as far as I remember, the delays were varied but acceptable.
(Someone has suggested that there may have been corruption of the TCP/IP settings on installing the firewall but I do not know what that means let alone if that could be the culprit.)

System details:
Processor 650 MHz Pentium III
RAM 128MB
Hard Drive 17GB
Modem Supra SST 56i Pro DF
Windows 98
IE 6.x
Connection: dialup
ISPs:
Waitrose.com via coper wire
Blueyonder (Telewest - fibre optic cable)

Problem occurrs with both ISP connections

Any ideas?

Chris Sanctuary