10.04 disables my BIOS password

Just a comment; I that were my situation, I'd start in BIOS and remove the administrative password so none is needed. Then restart the computer and see if either Windows or Ubuntu starts properly. If they both start okay, skip the BIOS password and make a password to log into Windows and another for Ubuntu. It's not as secure as a BIOS password, but I'd prefer the functionality of Windows and Ubuntu to losing one or the other. The tangle of BIOS vs double booting isn't worth the hassle.

You can also set a screensaver password in Windows that further guards your data. The ultimate is to only save data to an external drive and leave nothing in My Documents (Windows) or Documents (Ubuntu). If you're really spooked about security, also encrypt the external drive.

Otherwise, I have no suggestions on how to really solve your problem.

It looks me strange as neither Windows nor Ubuntu can access BIOS configuration.
So check problem is actually related to boot of Ubuntu.

As far as I know, BIOS settings can't be accessed from Windows or Ubuntu. When the computer first starts, use the F2 key or what it immediately indicates at the first black and white screen. By the time Windows or Ubuntu tries to load, BIOS has already set the current environment of drives, keyboard, mouse, etc. so you have to get to it before Windows or Ubuntu loads. Once in then reset the password from the Administration submenu.

Thanks David and delance,

I already have passwords for Windows and Ubuntu, including screensavers for both, even biometric, but since I have important information in my laptop I don't want anyone to even have access to launch a LiveCD to access my hard drive. That's why I want BIOS password protection.

And for 'ubuntu doesn't have access to BIOS' is what puzzles me. I guess you are right, but I have double checked: As long as only use Windows, the password remains enabled (suspend, logout, shutdown, resume, shutdown, force reset, crash, tried all combinations: still active). but as soon as I boot into my ubuntu installation, just once, the password remains in the BIOS, but it is now disabled, as well as the other changes I made, for instance, beep when I plug in the power adapter. Seems to me that BIOS somehow takes its default values. I mean, I get the same behavior if I enter the BIOS again (F2) and recall factory configutarion: the passwords are not erased, but goes disabled.

Confusing (memory collision, corruption?) don't know. That's why I ask instead of file a bug review request.

Whew! I guess it's time for you to file a bug report on this. A really annoying problem for you!

An update:

I've been working on the issue, and found if I boot with the user BIOS password instead of the supervisor BIOS password the problem doesn't occurs (at least for these couple of days). Will keep testing.

Now it happens every now and then...

Can you provide a link to a documentation, which talk about password for this computer ?
I have never saw BIOS with two password, and need to understand further.

Sure thing!

The BIOS has two passwords. At the security screen reads:
Set Supervisor password [Enter]
Ser User pasword [Enter]

Password at boot [enabled]

So when the computer boots ask for supervisor password. Here one can enter either the supervisor password or the user password. Both works for booting and working on the machine. The difference is the supervisor password allows the modification of the BIOS settings and the user password not.

Further info:
http://www.pcguide.com/ref/mbsys/bios/set/passwdSupervisor-c.html
http://www.pcguide.com/ref/mbsys/bios/set/passwdUser-c.html

http://consumerdl.lenovo.com.cn/UserFiles/UserGuide/en/User%27s%20guides%20and%20manuals/G450-G550/Lenovo%20G450-G550%20User%20Guide%20V1.0.pdf doesn't talk about BIOS.
I have no idea about problem, and think you should raise a bug.

A detail: you set BIOS password to protect data, but if your laptop is stolen, thief can extract disk and read it. The only way I know to protect a laptop is to encrypt the hard disk. I didn't check it for Ubuntu, but at installation Ubuntu allow you to set a disk password.

As far as my concern you are right: I should encrypt my info. i'm working on it (out of time at the moment).

But in regard to this trouble, I found a pattern: the problem arise when I hybernate windows and then boot into ubuntu. As soon as I shutdown ubuntu and resume Windows, the BIOS setting are restored to default settings (i.e. BIOS password present, but disabled). It happens independently if I use user BIOS password or supervisor BIOS password.

Now it really looks like a bug to me, but I don't know if its a Windows bug, or BIOS bug, or ubuntu bug.