Mouse lag when interacting with the web

[speedemon86]

A good friend of mine who I visit often recently started having serious issues with her entire system. I worked on it and managed to fix it almost entirely. I figured out the mouse lagging and the keyboard freezing was only when interacting with the web (AIM, loading pages, updating programs, etc.). A spybot scan and fix made the connection speed jump back up to normal (she has cable, which I'm entirely unfamiliar with, and I'm not the best with the NT system strucure, it seems so much more cluttered than good ole 9x), but the lag still persists, even if it's less noticeable (partly because things load up faster, and partly because I replaced the wireless mouse/keyboard with good ole wired ones).

The lag corresponds with a short and sudden spike in hardware interrupts (WinXP Home, system profile says SP1, but that's never been a problem, and it might be inaccurate), which a google search revealed a bunch of stuff that I wasn't able to really make any sense of. Something about the linksys NIC needing a dedicated IRQ instead of sharing, but the modem is wired, and the router is a D-link, not a linksys.

I haven't the slightest idea of how to find the modem or the router's hardware profiles, so I can't attempt to update the drivers, or interact with them in any other fashion.

I will, of course, gladly divulge relevant information, and massive appreciation in advance.

[speedemon86]

EDIT: I should note that when web activity gets intense enough (mostly with downloading 40MB+ files from MU, RS, etc.), the mouse will hang up entirely (or in less intense cases, for only a few seconds or so), but once the web activity is finished, simply unplugging and reconnecting it makes it work again.