Dell keyboard where is the 'hash' sign?

Change your language prefrenece to English (United States ) US Key Board)

poured water on the keys does not work because you need to change out the roll of the keyboard

Hello
The assainged key for 'hash" is "SHIFT - 3" If it showas any other symbol than this, the inside membrane of the keyboard is faulty. You should contact the deler or Acer service center to make it right. OK.
Here is it. I'm going to print a hash symbol here by holding down the Shift Key and the press the Digit key (3)
########## #############################################

Assuming you are in UK
Open Control Panel
Open Regional and Language Options
In Regional Options ensure English United Kingdom is selected in both options
In Languages click details and select English United Kingdom and remove US Keyboard

Hold down the ALT(ernate) GR(aphic) key -- to the right of the SPACE BAR on your keyboard.
Press the '2' key.
Release the '2' key.
Release the ALT GR key.
Does an '@' display?

Check that you are using the "American English" keyboard mapping.
Control Panel -> Regional options.

if you are talking about the piece between the keyboard and LCD it is the Center Hinge Cover.
http://cgi.ebay.com/DELL-LATITUDE-D630-HINGE-COVER-POWER-BUTTON-DT838-NEW-/320400679562?pt=LH_DefaultDomain_0&hash=item4a995e628a#ht_1728wt_905
the part that surrounds the keyboard, is the Palmrest Assembly
http://cgi.ebay.com/Dell-Latitude-D630-Palmrest-w-Touchpad-WM534-C-/120550624996?pt=LH_DefaultDomain_0&hash=item1c11608ee4#ht_1509wt_905

How do I access the backslash key on an american keyboard

The keyboard fix is easy, replace the keyboard, same for the battery.
Manual is here
http://support.dell.com/support/edocs/systems/latc610/sm_en/index.htm
you can buy a keyboard here
http://cgi.ebay.com/New-Keyboard-Dell-Latitude-C510-C540-C600-C610-C640-/170342472542?cmd=ViewItem&pt=PCA_Mice_Trackballs&hash=item27a933db5e#ht_2468wt_1202
battery here
http://cgi.ebay.com/66WHR-Battery-Dell-Latitude-C500-510-C540-C600-C610-/280475115213?cmd=ViewItem&pt=Laptop_Batteries&hash=item414d9e9ecd#ht_2340wt_1734
S-Video on that model pretty much requires a direct S-Video to TV connection, then enable the TV in the Display properties. If you are trying to use an adapter, it will not work

Replace the keyboard
http://cgi.ebay.com/Dell-Vostro-500-1400-1500-Inspiron-1318-Keyboard-JM629_W0QQitemZ170470394380QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item27b0d3ca0c#ht_2074wt_1165
http://support.dell.com/support/edocs/systems/ins1520/en/SM/keyboard.htm#wp1179980

Hi,
If the Keyboard was mixedup in msn only then there is no issue might be the Fn combination with the num lock or any other caused that.
If keyboard charectors are printed wrong in DOS also then there is the issue with K/b so check it in DOS.
You can check your keyboard by typing osk in run command and on screen k/b will be opened check if that is working fine then issue with the hardware and if this is also behaving like same then software issue.