Normally, the game runs fine, but when I use an item like the EMP or limpet mine, the game slows to a slideshow crawl. My specs should be more than significant.
1.8 Ghz Core 2 Duo
256 mb 8600m gs
4 GB RAM
Vista 64
Any help would be greatly appreciated.

Be sure to check out the addons... I'd highly recommend "Adblock Plus", which catches pretty much any kind of ad and lets you add new rules very easily should it miss one. Aside from that (and the gazillion of developer addons) I (of course) have the GoG enhancement, Chatzilla, Personas, Shareaholic, Quickproxy, Stylish, Ctrl-Tab and Ubiquity installed.

Well that driver thing was a huge mistake. Everything seemed fine till I walked away for 5 minutes and let the screensaver fire. When it came back, it looked like a CRT monitor with a 30hz refresh and scanlines everywhere.
Never did find out if it'd help ICB

I updated my drivers to the LV2G ones, but it didn't help.

I hope nothing is broken... it never caused any problems for me.

nah it seems okay, probably something weird HP did, I've seen a few hardware manufacturers who tinker ever so slightly and cause odd problems down the road.