Black screen of death, huh? There are soooo many possibilities, but some are more likely than others. A "no signal" to the monitor can mean a faulty video card or onboard video. This could be a driver conflict with the IE beta package (who knows what files they change in the beta, IE and the main file system of windows are closely tied). Or, you could have accidentally static shocked the motherboard or video card into faulty running- were you grounded?
That brings me to another question. Did you open the case when upgrading to wifi? Was it a PCI card or USB solution? Static can do nasty and unpredictable things to Mobos and cards.
Also, how many devices are currently running off of how much power? Is your power supply up to the task? If you have like 3 HDDs, DVD, CD, a high-power graphics cards, audio card, etc.....you could have been at the limit with most OEM power supplies (like 300 watts), and any other power drawing periphials could have crossed that fine line between stability and brownouts.
Check for driver conflicts first, because that requires no dissasembling to test.
Actually, before you do even that, check the monitor on another computer.....I feel dumb for not saying that first, but I'm lazy enough to not edit this.