Unable to create new "visible" partition

I have just purchased an Acer Aspire 8935g laptop, which comes with Windows Vista Home Premium 32bit (not sure why 64bit isn't supplied). It has two 500gb hard drives; Disk 0 and Disk 1. Disk 1 is empty and I have successfully created 3 partions on this drive. According to Vista's Disk Management tool, Disk 0 contains three partitions. The first and last are both EISA Configuration partitions and can't be seen through Windows Explorer. The 2nd (middle) partition is the C: partition on which Vista is installed.

I want to install Windows 7 RC 64bit in a dual boot configuration, so I used Disk Manager to shrink the C: partition and then create a new 100gb partition. I assigned it the drive letter B: (there are no floppy drives on the laptop). The new B: partition is visible, along with the original C: partition through Windows Explorer, until I reboot the laptop. The B: partition then disappears and Windows Explorer can no longer see it, however Disk Management shows it is still there but it no longer has a drive letter and is now an EISA Configuration partition. I thought this issue might be caused by the choice of drive letter so I tried again using a different letter (F: ). Each time the drive is only visible to Windows Explorer until the laptop is rebooted. I've also tried using a different partition management tool (Partition Wizard) but it makes no difference. I've tried creating the partition as logical and primary but to no avail.

Can someone please explain what is happening? Why can't I create a visible partition on my "O/S" drive?

You probably already have 4 primary partitions - which is the maximum in Vista. You will have to "downgrade" one of the other partitions.

My laptop actually has 6 primary partitions: 3 on disk 0 and 3 and disk 1. The existing 2 EISA Configuration partitions were both Primary as was the C: drive and when I created the three partitions on the 2nd disk they were created as Primary!

I have tried to create the new partition on disk 0 as both logical and primary but it makes no difference. In both cases the partition is created and is accessible to Windows Explorer. I don't get any messages telling me I can't create any more primary partitions. Only when the laptop reboots does the new partition become unavailable.

Something does not add up. Could you post a snip of your disk management?

I contacted Acer who tell me they don't support the creation of partitons on the main O/S drive as this will affect their recovery software! They went on to say that if I do change the way the recovery software works it would void the warranty!!!!

I'm absoluteley amazed. I have a state of the art laptop with 2 x 500gb disk drives. I can partition one of them, but not the one with the O/S as this will void the warranty.

Wow don't you just LOVE the things some companies do? Well you could try running Windows 7 on the other drive... Also, the Windows 7 install disk should be able to see the other partitions as well so you should still be able to test it out.