upgraded Windows Vista Home xps m1530 to Windows 7 Professional

Hi everyone.

I recently upgraded my xps m1530 from Windows 32-bit Vista Home version to the Windows 7 32-bit Professional version, and am having some issues I can't resolve. Here are my specs and issues; hopefully some of you have helpful suggestions.

Specs:

Intel® Core™ 2 Duo T5800 (2.0GHz/800Mhz FSB/2MB cache)
3GB Shared Dual Channel DDR2 SDRAM at 667MHz (2 Dimms)
High Resolution, glossy widescreen 15.4 inch LCD(1440x900) & 2MP Camera
256MB NVIDIA® GeForce® 8600M GT
Integrated Sound Blaster Audigy HD Software Edition
56 WHr 6-cell Lithium Ion Primary Battery
Dell Bluetooth Travel mouse
Dell Wireless 355 Bluetooth Internal (2.0+Enhanced Data Rate)

Issues:

1) The keyboard and mouse have a slight lag -- when I type in a text box in firefox, for example, sometimes the keyboard will lag behind or the space bar won't register (seems to be especially pronounced with the space bar, like I'm used to pressing it softly but now I have to press it harder). This happens in msn messenger too.
2) After the upgrade, the software for my webcam isn't installed and I'm not sure how to interact with my webcam.
3) I've tried recording audio in Sound Recorder, Audacity, and despite the microphone levels being boosted, the mic can't pick up my voice or sounds in the environment.
4) I've corrected my slow video by downloading and installing the latest NVIDIA GeForce 8600M GT driver.
5) I can't start up my laptop without the power supply attached, otherwise it crashes at the windows loading screen (sounds like the fan or hard drive progressively speeds up -- makes more noise, then finally shuts off).

I assume, based on 4), that all or most of these issues are a result of incorrect drivers. What drivers do I need to install to correct the above problems?

Cheers