While you're at it, you might want to check your cables. Old SATA cables can get loose pretty easily in my opinion, especially the cheap ones with no metal clip.
I have a new cable for the new drive, and a couple unopened backups - hopefully one of them will work fine.
You might want to check if all your ports are the same, I recently purchased some new hardware and the first port on my motherboard is SATA3, the rest is not.
How can I check that? The documentation just says, "Serial Attached ATA (SATA) drive connectors":
I only see two ports in my Device Manager: (but I physically see four ports on the motherboard, and the documentation mentions four)
The 'Storage Controllers' listed, are they the unused ones, or the used ones, or what?
[Edit:] @Mussi: Aha! Thou arte correct!
In a different PDF manual I just downloaded, it says:
SATA 1.0 and 2.0
SATA: 1.5 Gbps and 3.0 Gbps
Available devices: "..., Serial ATA drives (4), ..."
The manual is for the same computer (Dell Dimension E521), but seemingly a different hardware configuration than the one I bought (it mentions e-card readers and such),
so SATA0 and SATA1 are probably the 3.0 Gbps ports, and SATA2 and SATA3 are probably the 1.5 Gbps, so they say (without explaining why ) to put the harddrives in the SATA0 and SATA1 ports.
My computer came with both the harddrive and the DVD drive in the SATA0 and SATA1 ports; probably because of the configuration I chose, they just plugged them into the first two ports (the two fastest), because nothing else was using it. I'll just move the DVD drive to the 3rd port (labeled 'SATA2'), and plug the new harddrive into SATA0 (leaving the existing harddrive in the port it is already in).
Thanks Mussi! This means I have higher connection speeds than I initially thought.
I feel much better plugging a SATA III harddrive into a SATA II port, rather than plugging it into a SATA I port.