I'd need some help with something about my brother's HDD.
This is the situation: he decided to give Windows 7 a spin, while retaining his already existing WinXP installation (thus, creating a dual boot). To do so, he wanted to chip off 40 GBs from his HDD with the most free space (a Samsung HD321KJ with a capacity of 300 GB; currently, it is in one partition). He wanted to use Easus Partition Master for this (because we'd read how good it is and how much it works like the prized Partition Magic).
However, when he tried to create a new partition on the disk, the app seemed unable to do anything with it; all options were greyed out. It shows the options for other HDDs all right, but none for this one. Checking the properties, it stated it is a dynamic disk and that there are 0 KBytes free (which, of course, is not true). It's as if that drive didn't really exist.
I don't think the HDD is faulty; it works very well, no reading/writing problems whatsoever. May it be the app's fault? Or Windows'?
What do you suggest, what should we do to have that extra partition?
(If "use some other utility", then which one? I've heard most of the freeware ones automatically format the HDD on which you create the new partition...)

Try running it in administrator mode. Also post your dxdiag .... eeer, sorry, autopilot reply mode.
Anyway, I recommend downloading and burning an UCD (Ultimate Boot CD) from http://www.ultimatebootcd.com/. It comes with many partition tools.

I recommend just running windows 7, it will take all your existing programs and files and move them into a windows.old folder.
XP is nice and all, but he's going to have to make the jump to upgrade sooner or later if he wants to continue playing new pc games, and I'm certain there will be a point in time where Steam and GOG.com stop supporting Win XP.

He's on XP, not Vista.
I'll try that UCD thing for him (he's away for a few days), thanks!
@Weclock
He'll change eventually, but for now, he only wants to see how it looks, how it works etc.

The Windows 7 installer includes an excellent, user-friendly partitioning tool (first introduced with Vista) which I strongly recommend using rather than any third-party solution.
When running the Windows 7 installer (whether as a boot disc or from within Windows) choose to customise the installation and you will be taken to the partition manager. From there you can easily shrink or expand partitions by any amount you specify, and when you have made the necessary adjustments you just click on the partition you want to use and click "next"; Windows 7 will then format it appropriately and set up the boot loader and everything else for you. It really is that simple.

I can't wait til they do, honestly. I love the whole future OS' compatibility thing you get here..I hope Windows 8, 9, 10, etc become supported...I'm gonna be hankering for Stonekeep and the like when I'm a dirty old man, I know it.

Well it ain't really the end of the world.. :)
I'd verify it through a different partition tool most definitely. Even if it's just partition magic. Just double check that it can see it fine and dandy. I'd also just run your usual diagnostics.. chkdsk /f /r just to make sure theres nothing weird going on that could make it do something crazy.
It sounds almost firmware-ish in nature, which would show on the outside as having no immediate effect on your HD other than what you just described.. But then it could also be very likely a bug in the program. In that case, I think the best place to actually go to would be the Easeus forums and post the problem there and seek advice from those who are experts :)
(Typed when tired and falling asleep at keyboard.. so is probably a pretty poor post :))

From the petri knowledgebase
Warning: After you convert a basic disk to a dynamic disk, local access to the dynamic disk is limited to Windows XP Professional, Windows 2000 and Windows Server 2003. Additionally, after you convert a basic disk to a dynamic disk, the dynamic volumes cannot be changed back to partitions. You must first delete all dynamic volumes on the disk and then convert the dynamic disk back to a basic disk. If you want to keep your data, you must first back up the data or move it to another volume.
Damn this forum needs italics
Basically yeah, it's major backup & inconvenient reinstall time or install another HDD time

Hmm... It's odd, I don't remember I ever changed it to a dynamic disk (ususally, I handle computer stuff for my brother), yet it seems it is. I'll convince him to use some other HDD for this purpose (after moving file around to have 40GBs of free disk space...) then.
Still, even if it can't make any partitions, the program should allow me to mess with the drive, but it fails to do so.
Thanks to all. Which answer should I mark as solution now? Tough choice ;-).
@nimagraven
I also suspect it's the app's fault, as, for example, WinXP's built-in disk management software recognized it (tried it a while back).

I bought a 40 GB drive specifically for Win 7 and when I formatted it in XP Pro, it set it to a dynamic disk by default. Something I didn't realise until I went to install Win 7 (it won't install on a dynamic disk). I had to reformat that drive and use the Computer Manager (or whatever its actual English name is) to force the formatting of a basic disk.

this is why I make partitions with new drives, just silly partitions, if it's a 500gb disk, I'll make 4 100tb and one odd to fit the rest.

OK, I've decided what to do about you helpful people.
I'll mark Coelocanth's post as answer, as that one reminded me of the HDD's being being dynamic's being the problem. (Usually, I know my way around computers, but for some reason, I completely missed the fact that it was a dynamic disk (even though both Easus and WinXP's built-in manager said so).)
However, I'll give everyone else +1 rep for your contributions.

Thanks Dristvaan. Glad I helped to get you pointed in the right direction. :)