Click Ok's questions

I have some websites on AWS (Windows Server 2012 R2), and I'm trying setup a mail server. I have installed hMailServer, and in the guide say I need configure the DNS records for mail. I never needed setup email server from zero like now, then I'm a bit confused about the DNS records needed for this.

I read in some guide I will need A, MX and PTR records for this. Currently, my registar has only this records:

mydomain.com A 1.2.3.4  
www.mydomain.com A 1.2.3.4

Now, I think I will need create that records:

mail.mydomain.com A 1.2.3.4
mail.mydomain.com MX 10 mail.mydomain.com

My questions:

1. Am I doing correctly?
2. What about the PTR record? I needed?
3. I will/can use this "mail.mydomain.com" like above in SMTP, POP and IMAP? Or I will need create different DNS records for this?
4. How can I do/know if I did correctly? I was using mxtoolbox, but even there I dont understand if I need inform "mydomain.com" or "mail.mydomain.com" on the tests.

My customer lost a domain more or less one year ago. The domain was tais taken for some company and isn't used, and their is only "parked" with some dummy DNS.

Looks that company that taken the domain will not renew it, then my customer asked to me to watch when it happens and recover the domain.

I see some domain registar that have a service to "watch and capture" an expiring domain. My question are:

1. That kind of service is reliable?
2. How it works?
3. What you recommend?

Thanks you very much!

Let's that I've got the domain mydomain.com.

I want that when any visitor goes to
www.mydomain.com
xyz.mydomain.com
abc.mydomain.com
asd.mydomain.com
qwe.mydomain.com
etc...

the visitor will continue seeing "xyz.mydomain.com", but the real address will be "mydomain.com". my asp.net application will handle the differences between the addresses. I want that the subdomain can be anything.

The problem is: I'm using a shared host. They allow me to create subdomains and allow me to create some DNS records:

Address (A)
CNAME
Mail (MX)
IPV6 (AAAA)
TXT

Is it possible to set up my hosting to accept that asterisk/wildcards for subdomains? How do I do it?

When you use Process Explorer and minimize to tray, The icon turn itself in a graph of CPU utilization. I want to see that graph for network usage, specifically for internet usage. Example, I can download up to 100kb/s. I'm downloading an program at speed of 25kb/s, then I want see the graph with 25% of use of internet usage.

There is a simple and free program like this?

Edit I've found an "revived" version of FreeMeter here: FreeMeter Revival

I was reading this question when I thought: Some emergencies requires that you log on in e-mail or another sensitive sites in public internet computers. Remember that points:

1. You cannot install anything;
2. You will use probably internet explorer 6+
3. You will use probably Windows XP

I think that maybe an on-line service will met that requirements...

When doing backups, I get confused about the max character size of the disk label when recording CDs/DVDs. It's fixed size or follow some standard?

Do you know some GUI tool to create Hardlinks/SoftLinks/Junctions?

I was reading that question How do you know who or what is locking a remote file? and I remember that question... even in Windows7, the Windows doesn't show that program is locking the removable disk, so we cannot safely remove the hardware. There is some tool to solve this?