You should allways have backups of your important files on seperate media when making changes to partitons or installing operting systems.
The small partition was probably the suspend-to-disk partion. If you didn't get the program for creating it on a CD with the computer you may be able to download it from Dell's website. If you want to recreate it you may have to create it beofre other partitions so it is at the start of the disk.
>be fast it is too urgent!
A lack of planning on your part does not constitute an emergency on our part.
Windows is probably trying to read the contents of the harddrive and failing because the partition information is bad.
If you are willing to accept that all the files you had on the computer are gone the best way to proceed is probably to completly wipe the harddrive. If you write zeros over the first sectors of the disk windows thinks it is a brand new harddrive that has never been used and will give you the options to partition it.
I usually use a linux boot CD or floppy and do
dd if=/dev/zero of=/dev/hda
((hda is primary master drive, hdb is primary slave, hdc is secondary master etc)
There are other utilitys available for disk wiping such as
ultimate boot cd
If you want to try to get files back from the harddrive then your best bet is to get a 2.5" to 3.5" adaptor to put the harddrive from your laptop in aonther machine s a slave drive. Use the correct size screwdrivers when taking the caddy apart to get the harddrive out.
If you are very lucky the main partition will be ok and you will be able to copy files off. If not you will have to get some disk recovery tools and start work, it may be worth making a sector by sector copy of the drive to work on.