How do I get rid of the accounts created by the store from which I purchased my new machine?

Floor Models

There's nothing really wrong with purchasing the demonstration model of a computer from a retail store, if you don't mind that the hardware's a little used. Perhaps it has a few dings and dents from the hundreds of people that may have come along and played with the machine while it was on display, but as long as the computer's working okay and has some kind of warranty that you can live with, it might be a way to save a few dollars.

The software's another matter.

You need to consider the machine "used" because it has been; by hundreds of strangers. And you have no idea what those hundreds of strangers did to the machine. It's not unrealistic to think that some might have deposited some malware on the machine or visited malicious web sites that did so.

You could be purchasing a nest of malware along with a host of other problems.

The Right Solution: Reinstall

In all honesty, the store should offer a reinstall. Heck, a good store should insist on this.

Before you take delivery of the machine, the store should wipe the hard drive and install Windows from scratch, exactly as if you had just opened the original package from the factory. For a store that has its act together, this isn't really a lot of effort.

It may delay your ability to just walk out of the store with your new machine immediately, but trust me: the delay is well worth it.

If they don't do it, you should.

That, of course, means that they should provide you with all the discs that you need to reformat and reinstall Windows and all the applications. It's a little time consuming to do it yourself (perhaps you can negotiate a lower price), but as I said, if they don't do it, you should.

You're just not safe if you don't.

The Wrong Solution

I'm going to be blunt and call this the wrong solution because I believe so strongly that a clean install is the only safe approach to this situation.

Unfortunately, I know that many will not want to follow my advice and try to soldier on anyway.

My guess is that you do not have administrative access. That's quickly solved by the process outlined in I've lost the password to my Windows Administrator account, how do I get it back?: download a tool, burn a CD, reboot from that CD and use it to reset the administrator password, or the password to any other account on the machine.

Even if you were given the password to an account with administrative privileges, change it. There's probably a whole cadre of store employees that know it as well and who knows who they've told.

Once logged in as an account with administrative access, first create a new account that you will use as your own. A best practice is to leave that as a "Limited User Account", but if you prefer to give it the option of performing administrative tasks without having to supply a password each time, you can add it to the "Administrators" group.

Delete any other user accounts. Don't delete accounts that are there for system services (.net, sql and possibly similar accounts), but do delete the accounts that were obviously set up and used by and for the store that you purchased the machine from.

Now, install up-to-date anti-malware tools - both anti-virus and anti-spyware. Make sure that they're running with up-to-date databases and scan the heck out of your new machine.

Make sure that all Windows updates have been applied and scan for malware again.

And, of course, begin backing up regularly.

There's no way to be 100% certain that the machine doesn't have something on it that you don't want, or that it has everything on it that it should, but this is about as close as you can get without reformatting and reinstalling from scratch.

You know ... like I think you really should.