XP won't boot

I have a Dell Inspiron 8100 running XP Home Edition. I was trying to download and install SP2 when at the end of the install the machine rebooted and would not boot. I get to the 'XP' logo screen and then a blue screen reading "PROCESS1_INITIALIZATION_FAILED" followed by technical information: "Stop:0x0000006B (0xC000007A, 0x00000008, 0x00000000, 0x00000000)"

At this point I have tried: 1) running chkdsk /p and chkdsk /r from the console; 2) running fixboot from the console. All to no avail. I am considering running fixmbr . . . is that advisable?

Any other ideas are certainly welcome.