I cloned a 300GB XP boot drive on a 4GB Dell GX280 to a 500GB HD on a 1GB Dell Dimension 5000, but even in Safe Mode, when I try to start up from the 500GB, I get the 0x7b BSOD...

plug the HD in other PC and execute Scandisk Complete

link to external sources to help you stay safe (Avoid Internet fraud! ... must have an anti-spam filter that can block spam in double-byte ... But a little caution can go a long way towards avoiding malware exposure. ...... Windows 2000 server could not start because the following file is missing or corrupt: ...

While the system begins booting --before the xp logo shows, if it gets that far for you, hold down the F8 key. This will bring up a menu. Choose "start windows in safe mode with networking".
The OS will start in safe mode. run a virus scan, defrag and scandisk, then restart the system. If is still wont boot normally, do the same thing then run a registry fixing program such as uniblue registrybooster, then reboot. If it still won't boot you may have to format the drive and reinstall the OS. good luck.
PLEASE RATE THIS ADVICE WITH SOME THUMBS UP!!!

Your PC can support upto 4GB of RAM incase you are using vista or Windows 7 and if you are using win XP (32 bit) then only 3 GB is supported 1GB shall standby and also make sure that they are not more than 533 HHz
Kindly rate this solution
Thanks And Regards

from what you describe, they system will not shutdown. So try the following:

1. Boot to safe mode (F8 at boot) and then see if the system will reboot from the safe mode.
2. Boot to the Safe Mode again, Start RUN MSCONFIG, edit the startup group, (Basically uncheck all the items in the startup tab) reboot in the normal mode then see if it shutsdown. If it shutsdown normally, then start adding items back one at a time until you identify the items that were causing the items.

You might want to try going into setup and setting your boot drive options to DVD drive as your 1st, HD as 2nd and Floppy as 3rd. Put your windows disk in the DVD before boot and run the program from DVD.

try going into your BIOS and changing the boot sequence, it may be set to boot from floppy instead of harddrive. or you could just reinstall windows, but that sucks cuz then you lose all your data and programs. and not to be rude, but you shouldnt have bought a dell, they are full of problems.

Your old hard drive contained files used by the OS, as well as the OS itself. If you replaced that HD with another, and did not clone your existing install onto the new HD, then there is no boot record, nor is there anything to boot. It is not possible to just swap a HD and expect it to work without either cloning the old drive or performing a fresh install of an OS. The fact that it is detected by the BIOS is good, as you can install a new OS onto the new drive, or use a program like Ghost to clone your old drive's contents onto the new drive.

try to boot in the safe mode and tell me what happens

If you boot from the XP CD and choose the first repair option it will load to a DOS prompt. From there type "chkdsk /r" and press enter. This will run checkdisk on your hard drive and repair any problems that it finds. It will take 45 minutes or more depending on the size of your drive. Once it finishes type exit to reboot and remove the CD. Your computer should boot normally.