The b, n, space bar, tab, and function keys will not work on my Dell Inspiron 1720 laptop.

You don't say what program you are using, that doesn't respond, but clicking the left hand mouse key is normal to go to the next page (sideways). The space bar is not normally used for this function.

take the problem keys off and clean out under them

You need to check the specifications of your laptop it may not be able to run Windows 7.
You need these specs:

• 1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
  

• 1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit)
  

• 16 GB available hard disk space (32-bit) or 20 GB (64-bit)
  

• DirectX 9 graphics device with WDDM 1.0 or higher driver
  

your best bet is to buy a new keyboard. only £5 at tesco for a half decent one.

You can probably brighten the display easily by pressing the function key (fn) to the left of your space bar, and pressing one of the numbered function keys at top of key board. It would probably have something like a picture of a sun on it.

mybe you have accidentally press the dual video mode...in your unit there is a FN kay located near the ctrl and alt button....and from f1 to f12 locate that button that has a logo for minitor by pressing at the same time the FN key and that screen logo you find press it and release if see if that works.

Sounds like it is time to replace the keyboard. Pretty easy to do. Replacement keyboards are around $20 on ebay. http://support.dell.com/support/edocs/systems/ins1501/en/sm_en/keyboard.htm#wp1111863

Try the FN (function key) and the Nmlk (number lock Key) at the same time.

turn your keyboard upside down and tap it a few times. if that doesnt solve the problem repeat.

If it still won't work write back for more ideas.

good luck and please rate my answer. thanks.

this page will show you how to align the metal bracket in the ears on the keyboard. And it also shows how to assemble disassembled keys

http://www.irithm.com/Dell.key.replacement.B1.html

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