Windows XP Pro boot failure, repair install don't work

Dell Inspiron 6000, 1gb ram, 160gb seagate hard drive, 1.5ghz processor, Windows XP Pro
The computer tried to go into standby mode. After reboot & Initial Bios screen it gets black screen with a blinking cursor in the upper left corner. I have even gone all the way to repair install of XP Pro and after it goes through the entire file copying process and gets to the reboot phase, as soon as it reboots it goes to the black blinking cursor screen and back to square one. I replaced RAM with new sticks, new HDD with XP Pro bu same problems still since 2 years. Back up taken. I've gone through the bootcfg menu, nothing is making any difference!
Any help please?

Now i have 3 OS installations. The computer isn't even getting to the OS boot list. Maybe I need to find a way to delete the two unneeded OS installations?I just downloaded SeaTools for DOS from Seagate and it's running the "long test" on the PC's hard drive. It is 86 percent done and is taking a while; we'll see if that does anything

Hello DllD...
After the Seagate check ios complete, try the following...
Boot from the Windows XP installation CD.
At the "Welcome to Setup" screen, press R to start Recovery Console. Choose the installation to be repaired by number (usually 1) and press "Enter".
When you are asked for the Administrator password, leave it blank and press "Enter".
At the command prompt, type chkdsk /r and press "Enter". (Note the space before /r) The disk check operation will start.
This will be a very thorough check of the hard drive and the file system...be patient and let it complete. It may appear to hang or even back up a few times...this is normal. 60 to 90 minutes is not unusual for this check...it may take longer in some cases.
Once the check completes and you are back at the command prompt, type exit and press "Enter". Let your computer boot normally to Windows.

I have windows xp pro. Last night it worked fine. I got a popup from my AV software (AVG) about a trojan. I clicked on "heal" and didn't give it another thought. Later, my son tried to use the computer and it wouldn't boot up. It will go through most of the boot up process and then start all over. I've tried selecting "Safe Mode", etc, but to no avail. I do have xp pro on a laptop, but not sure if that will help.

I am unable to start up my Windows XP. Whenever I try to start my system I get the message where it apologizes for the inconvenience and ask me to start up in safe mode and all that stuff. However tried everything but none of them would work either. Now, how to start my system? I think its the problem of my hard disk because it happened to me before but at that time it was solved by scan disk.

Your problem seems to me a hard drive failure. Just replace your hard drive and see what happens. I know you have to reinstall your Windows and everything back.