Windows xp home/ sp3 update/ wont boot or F8

Hello,
My pc is self made and loaded with win xp home. I had update turned on, everything going fine until sp3 installed! After reboot the problems began...
1- "Windows unable to save data for the file C:\$Mft "
2- "Windows unable to save data for the file C:\$BitMap "
3- "Missing file urlmon.dll " then a screen asking me to find the file and tell it where it is

4- I wemnt to another pc and got on the internet to search for this type of problem.
5- While on the other pc another screen shot a triangle w/! in it... "Windows unable to save data for the file KB960714-IE7.log . PLease try to save this file elsewher".
6- Then "Delayed write failed" and the pc rebooted
7- The boot failed I got a black screen saying "Boot failed insert boot media and hit any key to reboot"
8- I thought this crazy so I went into setup and found that the boot drive had changed.
9- I change it back to the correct drive and rebooted

this is where I am now! When I boot the pc seems to go throughseveral steps but, the screen is always blank. I can't get into setup, I can't boot off of the Windows cd or the HD setup cd, no F8, no F1 no anything! It is running though! I also tried to reset the bios.

Thanks