swapping the master and slave drives

I've never did this, but maybe check into Get norton ghost or equall program, if you can get one last boot from the old hardrive you can copy it , then the put it right on your new hardrive. LIke I said check into it, I believe it will work this way.

Most drives ship with a utility disk that will enable you to do a data transfer from the old drive to the new one.  If you have corrupted data you won't want to copy it.  However, if it is starting to physically fail you may be able to salvage your data before it is completely gone.

What kind of drive is your new one?  I know Maxtor and Western Digital ship with a floppy that will help you do this really easily.  Once it starts, your data can be moved in as little as an hour.  It can be a lengthy process, be patient.

Can you tell everyone what OS you are running.  There are specific steps that could apply to different OSs.

Use Kiranghaq answer that is right but sometimes you might have to dissconect the slave drive all together and then place it back on the drive when you are finished. then depending on what OS your going to install i.e. 98 or there in between or WINXP. if it is any other OS I don't know ;(... if its 98 use a DOS boot disk and make sure the FDISK and FORMAT programs are on it and at the A:\ type in FDISK and follow the instructions.  If its WINXP boot up with cd in the drive and follow the instructions there.

Gee, people should be required to specify their OS right off the bat.

devils13 - It'd be nice to know what OS you're running, but here's the general idea of what i did when i bought a new hard drive.

I installed the new drive, and created 2 partitions so that I could 1) throw all the crap I wanted to save on the old drive, onto the new drive, and 2) keep a partition for the new OS installation.  There are a lot of ways to do this.

Then I moved all the stuff I wanted to save, from the old drive, to the new drive.

Then I used my OS CD to wipe the old drive clean, and installed into the new partition.

You should tell us what OS you're running, and if you're planning to keep the same OS or change to a new one. You should also tell us if you know about the master/slave jumper settings so we know where to point you towards.

If you do not want to physicall rearrange the harddisks you can set the boot sequence in BIOS to boot from the second harddrive (make sure that it reads something like A;D;C - The important thing is that D comes before C in sequence) - this will make sure it reads the boot sector of the second disk before reading the first one.

As for MBR's, you don't need to worry about that sort of thing if you install a fresh OS onto the drive.  

If you do not wish to do this then (if you have win 95 - 98) you can just copy the existing OS from the first HDD onto the second and then SYS the second drive (from a floppy just type "SYS C:" or "SYS D"" depending on which is your drive letter - this will make it "system bootable".  If you have NT, 2000 or XP, you can use the built in recovery console to restore the boot sector, maybee just reinstall the OS from scratch.

Another thing you wil need to do is set the primary boot partition to "active".  If both HDD's use the same IDE channel then you will need to disconnect the first HDD (or disable it in BIOS) and use FDISK to set the primary boot partition of the second HDD as active - disconnection is necessary as you cannot set another disk on the same channel as active if one active partition already exists on another disk.  Once this has been set, you can reconnect the first HDD.

Check that the boot sequence is set properly, that the primary dos partition is set as active, and that the disk is system bootable.

kiranghag's answer is right. If you can't get that to work for some reason you can try this:

sys (new drive letter):
and use the bios to decide what boots.

Remember though that only a master HD can boot.

Another thing that MIGHT work, is enable smart in the bios, if the HD hardware supports it.

If your question only refers to the MBR... fdisk /MBR in win98 will rewrite the MBR. If that's what you ask???

There are also some BIOS that will allow to boot from various hard drives without messing with jumpers.  You simply choose to the driver letter to boot from assuming all hard drives are ahead of other drives in the systems.  For example some systems let you specisfy boot order like d:,CD-ROM, USB or E:,CD-ROM, FLOPPY.  These are examples as many BIOS will support setting the boot order at this level.