Does anybody know if it is the computer, or just me?
No way of knowing. You did not describe your partitioning arrangement. Did you create some free space on the drive before you started the Ubuntu install? This is the usual approach if you are going to dual boot the system.
The Ubuntu installer should have a partitioning tool, however, if you are interested in saving the windoze install, you should have a backup, then use a partitioning tool like Partition Magic to shrink the windoze partition, leaving enough space for your Ubuntu install.
If you do not want to save the windoze system, then delete all partitions, boot the install CD for Ubuntu, and create the partitioning scheme you want, and install.
There are a few things that can cause problems, some systems BIOS cause problems, but there are usually work arounds.
Linux uses different file systems than windoze, so it is not free space on a windoze partition you want, but space not allocated to a partition.
Hope this helps.