microsoft essentials error :0x004ff91

at some point in the last month my security essentials disappeared and would not re install i followed all the help inputs but nothing is working now i cant bring malware back and my user screen is now locked up forced to run in safe mode have a list a mile long of errors from bios to auto update not working suspect missing or corrupt registry but burnt through fixit no result or my original vista is contaminated by to many incorrect updates bluescreen x2, to many codes to list,server communicate null network adapters as unknown device but with driver???,script line character undefined null not an object ?? registry size limit ok . hot fixes wow way to many is there an idiot proof way of starting over master reset push button done to heck with all my or my daughters data i just want to be able to use in normal mode oh ya almost forgot my (D:) drive some how became    (D:)(D:)    what the ???? yes i know get a new one well unemployment don't cover goodies like such any input at all will be appreciated  or just shoot me and the laptop do the laptop first though then i can go out satisfied oh duh 09/13/2007 presario c700/c714nr notebook pc windows 6.0build sp-2 by hp product of china processor intel(r)pentium(r) dual cpu *** Email address is removed for privacy *** 1467 mhz 2 core 2 logical processors sys type x86 based bios version f.08 smbios 2.4 with i luv corey painted on the top if that helps :) good day