Hi. Basically I did a PC for the brother-in-law and sister of a friend ...

XP1700+ @ XP2600+
KT400
512MB
80GB 7200-2 HD
Diamond 56iVpro (IIRC) 56K PCI modem
few other bits on WinXP_SP1

If you want to skip most of the background I'll BOLD the main stuff. Been running perfectly fine for several months but today they had problems with the Internet, random disconnects using Blueyonder unmetered. They're light users, pretty new to PCs so I don't think heavy usage is the cause. I suggested it was most likely the ISP problems so wait an hour and if still troublesome just try again tomorrow, then try phoning ISP Support. They waited an hour but problem still persisted so then called the ISP Support Line who got them to try a whole bunch of things but to no avail. They suggested it was either a problem with their PC or a DLL type file had become corrupt and they should call M$ for assistance (like they'd help). They called me back (9:45pm) and asked what to do. I asked if they'd changed anything recently and they said they installed Incredi-mail sw earlier today! I suggested it could be the cause though thought it was most likely just the ISP having issues or problem with their phone line. I suggested they use System Restore to roll back to yesterday or a few days ago, perhaps try uninstalling Incredi-mail (reinstall when ruled out) and see if it helps otherwise an OS reinstall (keeping their files and data) would be needed to rule out corrupt system files.

So basically has anybody come across this type of thing and is it possible for Incredi-mail or a corrupt file to cause random disconnections? Any advice? Thanks in advance.