First off have you gone to Dells site and found either Vista or Windows seven drivers
for it? If not then you'll need to install the XP as well as the Vista drivers in compatibility mode.Compatibility Mode
It would also be nice to know the make and model number of your keyboard and mouse as well as all the rest of your system specs for later on. You can fill them in here
You can use this program to help you out if needed http://www.piriform.com/speccy
Canned compressed air. Also before you try to remove your keyboard I suggest you Download your manual it might help with finding where the screws are and what cables to look for when removing it and how far you can move the keyboard before having to remove the cable ribbon(s).
If this is the same keyboard then here is another thread on it,if not I'm sure their are some suggestions that may apply Dell Studio 1535 keyboard driver