Henry Goodman wrote:

I have been running Seti 3.08 on a Windows 98 machine for years. Last
week I installed broadband and yesterday I installed McAfee Firewall
Plus 5.0.5.7 (broadband suppliers suggested I need a firewall and I am
already using McAfee VirusScan and Spamkiller)
The effect was to slow Seti to a crawl.
Does anybody know if this can be cured by switching to BOINC?

Please tell me you're not using a USB modem?!  Such things use a lot of
system resources, as do software firewalls.  You'd be much better off
buying a router. Such things have built-in ADSL modems and a hardware
firewall. Such a device would use drain zero CPU power, and would offer
hugely better protection.