Server Control Room Scam

[#1]

This is the second email I have received recently purporting to be from my email administrator, which I have copied below which is clearly a scam to elicit information from me;
Dear Email User
This mail is from your email Administrator; You have exceeded the storage limit on your mailbox.You will not be able to send or receive new mail until you upgrade your email quota.
we wish to bring to your notice the Condition of your email account. We have just noticed that you have exceeded your email Database limit of 500 MB quota and your email IP is causing conflict because it is been accessed in different server location. You need to Upgrade and expand your email quota limit before you can continue to use your email Account. Update your email quota limit to 2.6 GB, In order to ensure you do not experience service interruptions/ possible deactivation, please you must reply to this email immediately confirming your email account details below for confirmation/ identification
1. First Name & Last Name:
2. Email Address:
3. Username & Password:
4. Confirm your Current Password:
Failure to do this will result to email deactivation within 24hours Thank you for your understanding.
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[#2]

Thanks for the warning about this!
Have you scanned your computer for trojans?  You received these emails, so the spammers already have your email address.  They must be after your authentication details in order to send from your account?  Obviously don't reply (presumably it's too late to advise you not to even open emails like this).  If both examples were sent to the same address (eg 'identity@username...' ), then I would change the 'identity' part of the address I used and, as soon as my contacts had been given a new address, I would blackhole 'identity@username...'
HTH
Chris