The USB error may be contributing to the problem. Stop: 0x00000051 can be caused by hardware problems. First, turn off the computer. Unplug all devices except keyboard, mouse and monitor. Preferable to use PS/2 keyboard and mouse. Restart computer. See if you get error again. If you do, restart again. Press F8 (about 2 times a second) while Dell logo is on screen. If you can get to Safe Mode selection screen, select Last Known Good Configuration. Let us know what happens.
Good suggestion. I debated whether or not to mention UBCD or UBCD for Windows which of course uses Bart's PE. UBCD for Windows as you probably know requires XP SP2 unless you remark out the sdhcinst.dll file and associated registry entries in the BTSDrivers.inf file. Just used it today to fix a Stop: 0x0000007B error generated by a non-OEM replacement motherboard. Great for backing up data on otherwise inaccessible drives.