I had a similar problem updating from 10.04 to 11.04. I am using a 32bit
system and not a 64 though. Wonder if this could be my problem. Anyway luckly I
had a disc with 10.04 and was able to reinstall it and do all it's updates.

does anyone know if there is a problem with 11.04?

Upgrades are always iffy, IMO. I prefer fresh installations for that reason.
With 11.04 there are significant changes that could cause problems for some
users. These include the new UI with both Unity and Compiz being changed. I
would use the Live CD and backup all data and re-install, but you can also
use the Live CD to upgrade (new feature) or try the recovery mode from the
grub menu.

I tried several of the grub menu revs of Ubuntu and also recovery mode, no
luck.

I backup to an external USB HD then installed 11.04 64-bit from a Live CD.
There has been some big changes there, much simpler, I like it better. Also,
the D-Link DWA-125 works from the Live CD. Before I had to go in and do a
bunch of hokie-pokie stuff before it would work (praise to the Ubuntu team
on that). But then I did not get the multi-boot menu at boot but the monitor
complained that the supplied signal was not supported. After a little while
boot screens started to appear and there was the desktop.

While copying stuff back from the external USB HD to the 500GB HD I got a
disk-full complaint. What? Taking a look, there was only a few meg free.
What?

During the Live CD install the options where something like
Use all the drive
Use the 11.04 partition
Custom
I took the 11.04 figuring it was the former 10.10 upgraded. Apparently
WRONG.

Then I went back and done the install again. This time taking CUSTOM
partition, deleted all non-NTFS partitions and partitioned as per notes from
the original 10.10 install.

It still boots the same, without the grub menu, complaining about non
support of the video signal, but the memory is back, and so is all the stuff
that was on 10.10. That sure was a pleasant surprise.

Unfortunately there are three things that Windows can do that Ubuntu cannot,
FULL support for the HP 4500 printer, Tower Hobbies Real Flight (simulator)
and AVR Studio (software to program Atmel micro-controllers).I still need to
get the grub menu to work. How do I do that? I have installed grub. I would
hate to go back and re-install from scratch Windows and Ubuntu. I wish the
above three items were fully supported by Ubuntu then I would not need
Windows but I think there is a faint light at the end of this long dark
tunnel.

Think I have said this before but I will not upgrade till11.4 LTS comes
out in Sept I believe.

I'm with you and have gone back to 10.10.

Know what you mean and I'll not be upgrading my working system either
until the next LTS release but we've a bit longer to wait than
September this year - next one due is going to be 12.04 .. i.e. April
2012.

The beta's may be out in September but these again are not recommended
on a working system - especially the early ones