There's a big conspiracy thing you left out there,
mat.
Spoilage up ahead
Supposedly this group of hackers, called Praetorian, hack into and penetrate valueable systems such as the power grid, Airports, the stock market, etc.
People get worried, and install this new anti-virus/firewall/security software, like Norton. Billionaire Jeff Gregg (a play on the name Bill Gates, Jeff is a short common name like Bill, and last name starts with a G) goes on TV and says how important his software is, making the government install the software on their whole network.
What Angela Bennett (Sandra Bullock) finds out is that the program contains a backdoor, enabling the company/Praetorian to waltz right in, change arrest records, IRS forms, bank accounts. They use this to digitally erase her life, and frame her for numerous crimes.
She manages to sneak into her former office and trace the enemy group (by IP address, which leads her to a photo who it's registered under (Jeff Gregg)). Here is where you see her make windows on her Mac pop up and she types real fast, doing things like Traceroute and pingm while entering IP addresses greater than 300. Long story short, she copies all this evidence onto a floppy, and runs over to Macworld Expo in the Moscone Center, San Francisco.
She E-mails the FBI, attaching the files. The bad guy meets her at the kiosk, and shows her in front of her how easy it is to telnet (with a GUI?) into the servers with the backdoor and just as he's about to erase the e-mail...
Let me go back to the beginning and bring a small detail into light. She works as this beta tester/debugger for this software company, opening up a hex editor many times, as well as ResEdit to catch errors and fix them. So while she plays/tests Wolfenstein 3D, she's typing hex to fix an error here and there. She finds a virus that when you hit the Escape key, starts to erase all your files (see rm -rf /). She catches this virus and stops it from doing any harm, but copies it onto a floppy that gets sent to her office.
Back to the plot, the bad dude is opening the FBI e-mail to erase the evidence she e-mailed, but before he came she put in the same red disk the virus was on in the disk drive! He tells Angela that he could erase everything she sent to the FBI, "simply by escaping the system." With that, he confidently hits the Esc, and the virus kicks in, wiping all the files on the system. You're supposed to assume that the virus is also wiping out stuff on the FBI computer too, because the accomplice begins typing, saying that it's erasing the whole backdoor hack they put in. She escapes and the bad guys are all arrested or die. The end.