I saw another post here at techspot where the fellow was having the same problems. I told him to run the fdisk program. I googled the info from here and here it is:
From this trusty website:
http://www.ntfs.com/mbr-damaged.htm
The simplest way to repair or re-create MBR is to run Microsoft's standard utility called FDISK with a parameter /MBR, like
A:\> FDISK.EXE /MBR
FDISK is a standard utility included in MS-DOS, Windows 95, 98, ME.
If you have Windows NT / 2000 / XP, you can boot from startup floppy disks or CD-ROM, choose repair option during setup, and run Recovery Console. When you are logged on, you can run FIXMBR command to fix MBR.
end
Personally, though, I just use a win98 boot disk, even in win xp. Set bios to boot from floppy and use win 98 boot disk. Use the same fdisk command.
The command i use is: "fdisk /mbr" , without the quotes.
That is the correct procedure, although you can also do it using the win xp recovery console. I only use the win 98 boot floppy because that is what i have done for years.
This may solve your problems.
Is your ram matched or is it different speeds? Something is wrong there, so perhaps you might want to get that straightened out before doing the fdisk to repair your mbr (master boot record).
Do you have any antivirus program on your pc? Run that and have it check your mbr and it should show you if there is a problem with your mbr. If you dont have one you should. You can download a free a\virus prog from AVG, but you likely already know that and you likely do have an antivirus prog.
Again, i would save the mbr work until after you have dealt with the ram issue and checked your mbr with your antivirus prog.